Sentence-position effects on children's perception and production of English third person singular -s

Real-time spoken word recognition in deaf and hard of hearing preschoolers: Effects of phonological competition

This study investigates how phonological competition affects real-time spoken word recognition in deaf and hard of hearing (DHH) preschoolers compared to peers with hearing in the normal range (NH). Three-to-six-year olds (27 with NH, 18 DHH, including uni- and bilateral hearing losses) were instructed to look at pictures that corresponded to words alongside a phonological competitor (e.g., /bin-pin/) vs. an unrelated distractor (e.g., /toy-bed/). Phonological competitors contrasted in either voicing or place of articulation (PoA), in the onset or coda of the word. Relative to peers with NH, DHH preschoolers showed reduced looks to target in reaction to the spoken words specifically when competition was present. DHH preschoolers may thus, as a group, experience increased phonological competition during word recognition. There was no evidence that phonological properties (voicing vs. PoA, or onset vs. coda) differentially impacted word recognition.

Five Additional Evidence-Based Principles to Facilitate Grammar Development for Children With Developmental Language Disorder

PURPOSE

Because the development of grammatical forms is difficult for many children with developmental language disorder (DLD), language interventions often focus on supporting children's use of grammatical language. This article proposes five additional principles to those suggested by Fey et al. (2003) to facilitate the development of grammatical forms by children with DLD. Three of the five additional principles address the selection and presentation of linguistic contexts to be used with target grammatical forms (Principles 11-13); two principles encourage the incorporation of additional intervention components: auditory bombardment and explicit instruction (Principles 14 and 15, respectively).

METHOD

We present empirical evidence and, when available, describe the theoretical motivations to support each of the five additional principles. We then describe how we have integrated the five principles into 20- to 30-min intervention sessions that target regular past tense -ed, third-person singular -s, present progressive is/are verb+ing, or do/does questions for 4- to 8-year-olds with DLD. Each session includes four activities: sentence imitation, story retell, structured play, and auditory bombardment. We provide details of each activity, relevant materials, and illustrative examples that highlight the incorporation of each of the principles.

RESULTS

When targeting the development of grammatical forms in intervention, current evidence supports the use of a high degree of linguistic variability (Principle 11), the presentation of target forms in contexts that vary in difficulty (Principle 12), the presentation of target forms in sentences that vary in syntactic structure (Principle 13), the use of auditory bombardment (Principle 14), and the incorporation of explicit instruction (Principle 15). Clinicians can use these principles when targeting a range of grammatical forms in relatively short intervention sessions comprising a variety of activities.

CONCLUSIONS

This article encourages the employment of five additional principles into grammatical language intervention. Descriptions, materials, and examples demonstrate how the principles can all be addressed within a single intervention session.

Verbs Matter: A Tutorial for Determining Verb Difficulty

PURPOSE

Research indicates that when teaching grammatical forms to children, the verbs used to model specific grammatical inflections matter. When learning grammatical forms, children have higher performance when they hear many unique verb forms that vary in their frequency and phonological complexity. In this tutorial, we demonstrate a method for identifying and characterizing a large number of verbs based on their frequency and complexity.

METHOD

We selected verbs from an open-access database of transcribed child language samples. We extracted verbs produced by 5- to 8.9-year-old children in four morphosyntactic contexts: regular past tense -ed, third person singular -s, is/are + verb+ing, and do/does questions. We ranked verbs based on their frequency of occurrence across transcripts. We also coded the phonological complexity of each verb. We coded each verb as high or low frequency and high or low phonological complexity.

RESULTS

The synthesis yielded 129 unique verbs used in the regular past tense -ed context, 107 verbs used in the third person singular -s context, 69 verbs used in the is/are + verb+ing context, and 16 verbs used in the do/does question context. We created tables for each form that include the frequency rankings and phonological complexity scores for every verb.

CONCLUSIONS

Clinicians may use the verb lists, frequency ratings, and phonological complexity scores to help identify verbs to incorporate into assessment and intervention sessions with children. Researchers and clinicians may use the step-by-step approach presented in the tutorial to identify verbs or other syntactic components used in different morphosyntactic contexts or produced by individuals of different demographics in different speaking contexts.

Converging Evidence of Underlying Competence: Comprehension and Production in the Acquisition of Spanish Subject-Verb Agreement

A surprising comprehension-production asymmetry in subject-verb (SV) agreement acquisition has been suggested in the literature, and recent research indicates that task-specific as well as language-specific features may contribute to this apparent asymmetry across languages. The present study investigates when during development children acquiring Mexican Spanish gain competence with 3^rd-person SV agreement, testing production as well as comprehension in the same children aged between 3;6 and 5;7 years, and whether comprehension of SV agreement is modulated by the sentential position of the verb (i.e., medial vs. final position). Accuracy and sensitivity analyses show that comprehension performance correlates with SV agreement production abilities, and that comprehension of singular and plural third-person forms is not influenced by the sentential position of the agreement morpheme. Issues of the appropriate outcome measure and the role of structural familiarity in the development of abstract representations are discussed.

Cue reliability, salience and early comprehension of agreement: Evidence from Greek

Previous studies across languages (English, Spanish, French) have argued that perceptual salience and cue reliability can explain cross-linguistic differences in early comprehension of verbal agreement. Here we tested this hypothesis further by investigating early comprehension in Greek, where markers have high salience and reliability (compared to Spanish and English) predicting early comprehension, as in French. We investigated two and three-year-old Greek-speaking children's ability to distinguish third person singular and plural agreement in a picture-selection task. We also examined the frequency of these morphemes in child-directed speech to address input effects. Results showed that three-year-olds are sensitive to both singular and plural agreement, earlier than children acquiring English and Spanish, but later than French, and despite singular agreement being more frequent than plural agreement in the child corpus. These findings provide further support for the role of salience and reliability during early acquisition, while highlighting a potential effect of morpheme position.

Comprehension of the copula: preschoolers (and sometimes adults) ignore subject-verb agreement during sentence processing

Subject-verb (SV) agreement helps listeners interpret the number condition of ambiguous nouns (The sheep is/are fat), yet it remains unclear whether young children use agreement to comprehend newly encountered nouns. Preschoolers and adults completed a forced choice task where sentences contained singular vs. plural copulas (Where is/are the [novel noun(s)]?). Novel nouns were either morphologically unambiguous (tup/tups) or ambiguous (/geks/ = singular: gex / plural: gecks). Preschoolers (and some adults) ignored the singular copula, interpreting /ks/-final words as plural, raising questions about the role of SV agreement in learners' sentence comprehension and the status of is in Australian English.

The Acquisition of Productive Plural Morphology by Children With Hearing Loss

Purpose Normal-hearing (NH) children acquire plural morphemes at different rates, with the segmental allomorphs /-s, -z/ (e.g., cat-s) being acquired before the syllabic allomorph /-əz/ (e.g., bus-es). Children with hearing loss (HL) have been reported to show delays in the production of plural morphology, raising the possibility that this might be due to challenges acquiring different types of lexical/morphological representations. This study therefore examined the comprehension of plural morphology by 3- to 7-year-olds with HL and compared this with performance by their NH peers. We also investigated comprehension as a function of wearing hearing aids (HAs) versus cochlear implants (CIs). Method Participants included 129 NH children aged 3-5 years and 25 children with HL aged 3-7 years (13 with HAs, 12 with CIs). All participated in a novel word two-alternative forced-choice task presented on an iPad. The task tested comprehension of the segmental (e.g., teps, mubz) and syllabic (e.g., kosses) plural, as well as their singular counterparts (e.g., tep, mub, koss). Results While the children with NH were above chance for all conditions, those with HL performed at chance. As a group, the performance of the children with HL did not improve with age. However, results suggest possible differences between children with HAs and those with CIs, where those with HAs appeared to be in the process of developing representations of consonant-vowel-consonant singulars. Conclusions Results suggest that preschoolers with HL do not yet have a robust representation of plural morphology for words they have not heard before. However, those with HAs are beginning to access the singular/plural system as they get older.

Phonological selectivity in the acquisition of English clusters

Phonological selectivity is a phenomenon where children preselect which target words they attempt to produce. The present study examines selectivity in the acquisition of complex onsets and codas in English, and specifically in the acquisition of biconsonantal (CC) clusters in each position compared to triconsonantal (CCC) clusters. The data come from the naturalistic productions of three English-speaking children. The results indicate that children only attempt to produce target tokens with a CCC onset after they have successfully produced target tokens with a CC onset, and that the same occurs in the case of codas. Frequency, morphological complexity, sonority, and /s/ clusters were examined and ruled out as possible explanations of these acquisition patterns. Overall, this suggests that children are selective in their target words, and only attempt to produce words that contain a cluster after they have produced words containing a shorter cluster of the same type (i.e., onset/coda).

Emerging word segmentation abilities in European Portuguese-learning infants: new evidence for the rhythmic unit and the edge factor

Word segmentation plays a crucial role in language acquisition, particularly for word learning and syntax development, and possibly predicts later language abilities. Previous studies have suggested that this ability develops differently across languages, possibly affected by the languages' rhythmic properties (Rhythmic Segmentation Hypothesis) and target word location in the prosodic structure (Edge Hypothesis). The present study investigates early word segmentation in a language, European Portuguese, that exhibits both stress- and syllable-timed properties, as well as strong cues to both higher-level prosodic boundaries and the word level. Infants aged 4-10 months old were tested with target words located in utterance-medial and utterance-final positions. Evidence for word segmentation was found early in development but only for utterance-edge located target words, suggesting the more salient prosodic cues play a crucial role. There was some evidence for segmentation in utterance-medial position by 10 months, demonstrating that this ability is not yet fully developed, possibly due to mixed rhythmic properties.

Development of perception and perceptual learning for multi-timescale filtered speech

The perception of temporally changing auditory signals has a gradual developmental trajectory. Speech is a time-varying signal, and slow changes in speech (filtered at 0-4 Hz) are preferentially processed by the right hemisphere, while the left extracts faster changes (filtered at 22-40 Hz). This work examined the ability of 8- to 19-year-olds to both perceive and learn to perceive filtered speech presented diotically for each filter type (low vs high) and dichotically for preferred or non-preferred laterality. Across conditions, performance improved with increasing age, indicating that the ability to perceive filtered speech continues to develop into adolescence. Across age, performance was best when both bands were presented dichotically, but with no benefit for presentation to the preferred hemisphere. Listeners thus integrated slow and fast transitions between the two ears, benefitting from more signal information, but not in a hemisphere-specific manner. After accounting for potential ceiling effects, learning was greatest when both bands were presented dichotically. These results do not support the idea that cochlear implants could be improved by providing differentially filtered information to each ear. Listeners who started with poorer performance learned more, a factor which could contribute to the positive cochlear implant outcomes typically seen in younger children.

Relationship of Grammatical Context on Children's Recognition of s/z-Inflected Words

BACKGROUND

Access to aided high-frequency speech information is currently assessed behaviorally using recognition of plural monosyllabic words. Because of semantic and grammatical cues that support word+morpheme recognition in sentence materials, the contribution of high-frequency audibility to sentence recognition is less than that for isolated words. However, young children may not yet have the linguistic competence to take advantage of these cues. A low-predictability sentence recognition task that controls for language ability could be used to assess the impact of high-frequency audibility in a context that more closely represents how children learn language.

PURPOSE

To determine if differences exist in recognition of s/z-inflected monosyllabic words for children with normal hearing (CNH) and children who are hard of hearing (CHH) across stimuli context (presented in isolation versus embedded medially within a sentence that has low semantic and syntactic predictability) and varying levels of high-frequency audibility (4- and 8-kHz low-pass filtered for CNH and 8-kHz low-pass filtered for CHH).

RESEARCH DESIGN

A prospective, cross-sectional design was used to analyze word+morpheme recognition in noise for stimuli varying in grammatical context and high-frequency audibility. Low-predictability sentence stimuli were created so that the target word+morpheme could not be predicted by semantic or syntactic cues. Electroacoustic measures of aided access to high-frequency speech sounds were used to predict individual differences in recognition for CHH.

STUDY SAMPLE

Thirty-five children, aged 5-12 yrs, were recruited to participate in the study; 24 CNH and 11 CHH (bilateral mild to severe hearing loss) who wore hearing aids (HAs). All children were native speakers of English.

DATA COLLECTION AND ANALYSIS

Monosyllabic word+morpheme recognition was measured in isolated and sentence-embedded conditions at a +10 dB signal-to-noise ratio using steady state, speech-shaped noise. Real-ear probe microphone measures of HAs were obtained for CHH. To assess the effects of high-frequency audibility on word+morpheme recognition for CNH, a repeated-measures ANOVA was used with bandwidth (8 kHz, 4 kHz) and context (isolated, sentence embedded) as within-subjects factors. To compare recognition between CNH and CHH, a mixed-model ANOVA was completed with context (isolated, sentence-embedded) as a within-subjects factor and hearing status as a between-subjects factor. Bivariate correlations between word+morpheme recognition scores and electroacoustic measures of high-frequency audibility were used to assess which measures might be sensitive to differences in perception for CHH.

RESULTS

When high-frequency audibility was maximized, CNH and CHH had better word+morpheme recognition in the isolated condition compared with sentence-embedded. When high-frequency audibility was limited, CNH had better word+morpheme recognition in the sentence-embedded condition compared with the isolated condition. CHH whose HAs had greater high-frequency speech bandwidth, as measured by the maximum audible frequency, had better word+morpheme recognition in sentences.

CONCLUSIONS

High-frequency audibility supports word+morpheme recognition within low-predictability sentences for both CNH and CHH. Maximum audible frequency can be used to estimate word+morpheme recognition for CHH. Low-predictability sentences that do not contain semantic or grammatical context may be of clinical use in estimating children's use of high-frequency audibility in a manner that approximates how they learn language.

Why do children pay more attention to grammatical morphemes at the ends of sentences?

Children pay more attention to the beginnings and ends of sentences rather than the middle. In natural speech, ends of sentences are prosodically and segmentally enhanced; they are also privileged by sensory and recall advantages. We contrasted whether acoustic enhancement or sensory and recall-related advantages are necessary and sufficient for the salience of grammatical morphemes at the ends of sentences. We measured 22-month-olds' listening times to grammatical and ungrammatical sentences with third person singular -s. Crucially, by cross-splicing the speech stimuli, acoustic enhancement and sensory and recall advantages were fully crossed. Only children presented with the verb in sentence-final position, a position with sensory and recall advantages, distinguished between the grammatical and ungrammatical sentences. Thus, sensory and recall advantages alone were necessary and sufficient to make grammatical morphemes at ends of sentences salient. These general processing constraints privilege ends of sentences over middles, regardless of the acoustic enhancement.

Influences of Phonological Context on Tense Marking in Spanish-English Dual Language Learners

PURPOSE

The emergence of tense-morpheme marking during language acquisition is highly variable, which confounds the use of tense marking as a diagnostic indicator of language impairment in linguistically diverse populations. In this study, we seek to better understand tense-marking patterns in young bilingual children by comparing phonological influences on marking of 2 word-final tense morphemes.

METHOD

In spontaneous connected speech samples from 10 Spanish-English dual language learners aged 56-66 months (M = 61.7, SD = 3.4), we examined marking rates of past tense -ed and third person singular -s morphemes in different environments, using multiple measures of phonological context.

RESULTS

Both morphemes were found to exhibit notably contrastive marking patterns in some contexts. Each was most sensitive to a different combination of phonological influences in the verb stem and the following word.

CONCLUSIONS

These findings extend existing evidence from monolingual speakers for the influence of word-final phonological context on morpheme production to a bilingual population. Further, novel findings not yet attested in previous research support an expanded consideration of phonological context in clinical decision making and future research related to word-final morphology.

The Role of Frequency in Learning Morphophonological Alternations: Implications for Children With Specific Language Impairment

PURPOSE

The aim of this article was to explore how the type of allomorph (e.g., past tense buzz[d] vs. nod[əd]) influences the ability to perceive and produce grammatical morphemes in children with typical development and with specific language impairment (SLI).

METHOD

The participants were monolingual Australian English-speaking children. The SLI group included 13 participants (mean age = 5;7 [years;months]); the control group included 19 children with typical development (mean age = 5;4). Both groups performed a grammaticality judgment and elicited production task with the same set of nonce verbs in third-person singular and past tense forms.

RESULTS

Five-year-old children are still learning to generalize morphophonological patterns to novel verbs, and syllabic /əz/ and /əd/ allomorphs are significantly more challenging to produce, particularly for the SLI group. The greater phonetic content of these syllabic forms did not enhance perception.

CONCLUSIONS

Acquisition of morphophonological patterns involving low-frequency allomorphs is still underway in 5-year-old children with typical development, and it is even more protracted in SLI populations, despite these patterns being highly predictable. Children with SLI will therefore benefit from targeted intervention with low-frequency allomorphs.

Effects of Type of Agreement Violation and Utterance Position on the Auditory Processing of Subject-Verb Agreement: An ERP Study

Previous ERP studies have often reported two ERP components-LAN and P600-in response to subject-verb (S-V) agreement violations (e.g., the boys (*) runs). However, the latency, amplitude and scalp distribution of these components have been shown to vary depending on various experiment-related factors. One factor that has not received attention is the extent to which the relative perceptual salience related to either the utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or the type of agreement violation (errors of omission vs. errors of commission) may influence the auditory processing of S-V agreement. The lack of reports on these effects in ERP studies may be due to the fact that most studies have used the visual modality, which does not reveal acoustic information. To address this gap, we used ERPs to measure the brain activity of Australian English-speaking adults while they listened to sentences in which the S-V agreement differed by type of agreement violation and utterance position. We observed early negative and positive clusters (AN/P600 effects) for the overall grammaticality effect. Further analysis revealed that the mean amplitude and distribution of the P600 effect was only significant in contexts where the S-V agreement violation occurred utterance-finally, regardless of type of agreement violation. The mean amplitude and distribution of the negativity did not differ significantly across types of agreement violation and utterance position. These findings suggest that the increased perceptual salience of the violation in utterance final position (due to phrase-final lengthening) influenced how S-V agreement violations were processed during sentence comprehension. Implications for the functional interpretation of language-related ERPs and experimental design are discussed.

Revise and resubmit: how real-time parsing limitations influence grammar acquisition

We present the results from a three-day artificial language learning study on adults. The study examined whether sentence-parsing limitations, in particular, difficulties revising initial syntactic/semantic commitments during comprehension, shape learners' ability to acquire a language. Findings show that both comprehension and production of morphology pertaining to sentence argument structure are delayed when this morphology consistently appears at the end, rather than at the beginning, of sentences in otherwise identical grammatical systems. This suggests that real-time processing constraints impact acquisition; morphological cues that tend to guide linguistic analyses are easier to learn than cues that revise these analyses. Parallel performance in production and comprehension indicates that parsing constraints affect grammatical acquisition, not just real-time commitments. Properties of the linguistic system (e.g., ordering of cues within a sentence) interact with the properties of the cognitive system (cognitive control and conflict-resolution abilities) and together affect language acquisition.

The role of sentence position, allomorph, and morpheme type on accurate use of s-related morphemes by children who are hard of hearing

PURPOSE

Production accuracy of s-related morphemes was examined in 3-year-olds with mild-to-severe hearing loss, focusing on perceptibility, articulation, and input frequency.

METHOD

Morphemes with /s/, /z/, and /ɪz/ as allomorphs (plural, possessive, third-person singular -s, and auxiliary and copula "is") were analyzed from language samples gathered from 51 children (ages: 2;10 [years;months] to 3;8) who are hard of hearing (HH), all of whom used amplification. Articulation was assessed via the Goldman-Fristoe Test of Articulation-Second Edition, and monomorphemic word final /s/ and /z/ production. Hearing was measured via better ear pure tone average, unaided Speech Intelligibility Index, and aided sensation level of speech at 4 kHz.

RESULTS

Unlike results reported for children with normal hearing, the group of children who are HH correctly produced the /ɪz/ allomorph more than /s/ and /z/ allomorphs. Relative accuracy levels for morphemes and sentence positions paralleled those of children with normal hearing. The 4-kHz sensation level scores (but not the better ear pure tone average or Speech Intelligibility Index), the Goldman-Fristoe Test of Articulation-Second Edition, and word final s/z use all predicted accuracy.

CONCLUSIONS

Both better hearing and higher articulation scores are associated with improved morpheme production, and better aided audibility in the high frequencies and word final production of s/z are particularly critical for morpheme acquisition in children who are HH.

Growth of finiteness in the third year of life: replication and predictive validity

PURPOSE

The authors of this study investigated the validity of tense and agreement productivity (TAP) scoring in diverse sentence frames obtained during conversational language sampling as an alternative measure of finiteness for use with young children.

METHOD

Longitudinal language samples were used to model TAP growth from 21 to 30 months of age for 37 typically developing toddlers. Empirical Bayes (EB) linear and quadratic growth coefficients and child sex were then used to predict elicited grammar composite scores on the Test of Early Grammatical Impairment (TEGI; Rice & Wexler, 2001) at 36 months.

RESULTS

A random-effects quadratic model with no intercept best characterized TAP growth, replicating the findings of Rispoli, Hadley, and Holt (2009). The combined regression model was significant, with the 3 variables accounting for 55.5% of the variance in the TEGI composite scores.

CONCLUSION

These findings establish TAP growth as a valid metric of finiteness in the 3rd year of life. Developmental and theoretical implications are discussed.

The role of utterance length and position in 3-year-olds' production of third person singular -s

PURPOSE Evidence from children's spontaneous speech suggests that utterance length and utterance position may help explain why children omit grammatical morphemes in some contexts but not others. This study investigated whether increased utterance length (hence, increased grammatical complexity) adversely affects children's third person singular -s production in more controlled experimental conditions. METHOD An elicited imitation task with 12 Australian English-speaking children ages 2;9 (years;months) to 3;2 (Mage = 2;11) was conducted comparing third person singular -s production in 3-word and 5-word utterances, both utterance medially (e.g., He sits back; He sits back and swings) and utterance finally (e.g., There he sits; That's the way he sits) using a within-subjects design. Children were shown pictorial representations of each utterance on a computer and were invited to repeat 16 pseudorandomized prerecorded utterances. Acoustic analysis determined the presence/absence and duration of the third person singular morpheme. RESULTS Third person singular production was significantly lower utterance medially compared to utterance finally for the 5-word utterances and significantly lower utterance medially in the 5-word compared to 3-word utterances. CONCLUSION These results suggest that increased utterance length results in significantly lower third person singular production, but only in the more articulatorily challenging utterance-medial position. Thus, morpheme omission is greatest at the intersection of grammatical and phonological complexity.

Grammatical outcomes of 3- and 6-year-old children who are hard of hearing

PURPOSE

Spoken language skills of 3- and 6-year-old children who are hard of hearing (HH) were compared with those of children with normal hearing (NH).

METHOD

Language skills were measured via mean length of utterance in words (MLUw) and percent correct use of finite verb morphology in obligatory contexts based on spontaneous conversational samples gathered from 185 children (145 HH, 40 NH). Aided speech intelligibility index (SII), better-ear pure-tone average (BE-PTA), maternal education, and age of amplification were used to predict outcomes within the HH group.

RESULTS

On average, the HH group had MLUws that were 0.25-0.5 words shorter than the NH group at both ages, and they produced fewer obligatory verb morphemes. After age, aided SII and age of amplification predicted MLUw. Aided SII and BE-PTA were not interchangeable in this analysis. Age followed by either BE-PTA or aided SII best predicted verb morphology use.

CONCLUSIONS

Children who are HH lag behind their peers with NH in grammatical aspects of language. Although some children appear to catch up, more than half of the children who are HH fell below the 25th percentile. Continued monitoring of language outcomes is warranted considering that children who are HH are at increased risk for language learning difficulties.

Acoustic investigations into the later acquisition of syllabic -es plurals

PURPOSE

Children acquire /-z/ syllabic plurals (e.g., bus es) later than /-s, -z/ segmental plurals (e.g., cat s, dog s). In this study, the authors explored whether increased syllable number or segmental factors best explains poorer performance with syllabic plurals.

METHOD

An elicited imitation experiment was conducted with 14 two-year-olds involving 8 familiar disyllabic target plural nouns, half with syllabic plurals (e.g., bus → bus es) and half with segmental plurals (e.g., letter → letter s). Children saw pictures of the target items on a computer and repeated prerecorded 3-word-utterances with the target word in utterance-medial position (e.g., "The buses come") and utterance-final position (e.g., "Hear the buses"). Acoustic analysis determined the presence or absence of the plural morpheme and its duration.

RESULTS

Children had more trouble producing syllabic plurals compared with segmental plurals. Errors were especially evident in the utterance-medial position, where there was less time for the child to perceive/produce the word in the absence of phrase-final lengthening and where planning for the following word was still required.

CONCLUSIONS

The results suggested that articulatory difficulties-rather than a word length effect-explain later acquisition of syllabic plurals relative to segmental plurals. These findings have implications for the nature of syllabic plural acquisition in children with hearing impairments and specific language impairment.

Sequence and system in the acquisition of tense and agreement

PURPOSE

The relatedness of tense morphemes in the language of children younger than 3 years of age is a matter of controversy. Generativist accounts predict that the morphemes will be related, whereas usage-based accounts predict the absence of relationships. This study focused on the increasing productivity of the 5 morphemes in the tense productivity score (copula BE, third-person singular present - 3s, past - ed, auxiliary DO, auxiliary BE; Hadley & Short, 2005) and their relationship to one another.

METHOD

Twenty typically developing children were observed longitudinally from 21 to 33 months of age. One hour of naturalistic caregiver-child interaction sampled every 3 months was analyzed.

RESULTS

Copula BE was more productive than all other morphemes from age 27 months onward. Auxiliary BE was significantly less productive than - 3s, - ed, and DO from age 27 months onward. Evaluation of third-person singular tense morphemes at age 33 months revealed that the productivity scores of copula is, - 3s, and does were all correlated.

CONCLUSIONS

There is sequence and simultaneity in development that no prior framework has fully explained, as well as evidence of cross-morpheme relationships. In this article, the authors interpret these findings as support for the gradual morphosyntactic learning hypothesis ( Rispoli & Hadley, 2011; Rispoli, Hadley, & Holt, 2009).

Acoustic evidence for positional and complexity effects on children's production of plural -s

PURPOSE

Some variability in children's early productions of grammatical morphemes reflects phonological factors. For example, production of 3rd person singular -s is increased in utterance-final versus utterance-medial position and in simple versus cluster codas (e.g., sees vs. hits). Understanding the factors that govern such variability is an important step toward modeling developmental processes. In this study, the authors examined the generality of these effects by determining whether position and coda complexity influence production of plural -s, which phonologically manifests the same as 3rd person singular -s.

METHOD

The authors used an elicited imitation task to examine the speech of 16 two-year-olds. Eight plural nouns (half contained simple codas, half contained cluster codas) were elicited utterance-medially and utterance-finally. Acoustic analysis of each noun was used to identify acoustic cues associated with coda production.

RESULTS

Results showed that plural production was more robust in utterance-final versus utterance-medial position but equally robust in simple versus cluster codas.

CONCLUSIONS

These findings extend positional effects on morpheme production to plural -s. An effect of coda complexity was not observed for plural but was observed for 3rd person singular, which raises the possibility that the morphological representation proper influences the degree to which phonological factors affect morpheme production.