Acoustic investigations into the later acquisition of syllabic -es plurals

Produced, but not 'productive': Mandarin-speaking pre-schoolers' challenges acquiring L2 English plural morphology

It is often assumed that pre-schoolers learn a second language (L2) with ease, even for structures that are absent in their L1, such as Mandarin-speaking pre-schoolers learning L2 English grammatical inflections (e.g., ducks, horses). However, while the results from Study 1 showed that such learners can imitate plural words (age = 3;5, N = 20), Studies 2 and 3 showed that they cannot yet generate or comprehend plural morphology (Study 2: age = 4;8, N = 20; Study 3: age = 4;1, N = 20), raising questions about when this is achieved. These findings have important implications for school readiness, as well as for identifying those at risk of developmental language disorders.

Preschoolers' developing comprehension of the plural: The effects of number and allomorphic variation

Previous intermodal preferential looking (IPL) studies have found that children learning English acquire knowledge of plural allomorphs incrementally. The segmental plural /-s/ (e.g., cats) is understood at 24 months of age, whereas the syllabic plural /-əz/ (e.g., buses) is not comprehended until 36 months. Production studies also show ongoing challenges with the syllabic plural /-əz/, suggesting a prolonged weaker representation for this allomorph. IPL studies also suggest that children do not understand the singular, which has no overt marking, until 36 months of age. However, the status of children's developing representations of the singular has been largely unstudied. The current study, therefore explored 116 3- and 4-year-olds' developing comprehension of novel singular and plural words, where the plurals were inflected with segmental and syllabic plural allomorphs. Results found that children were equally proficient at identifying novel plurals of both allomorph types, increasing accuracy with age. However, children's accuracy with novel singulars did not increase with age, raising questions about the representation of null morphology. Children's equal accuracy across plural allomorphs is more consistent with rule-based models of morphological representation than those proposing morphology as an emergent property of the lexicon. However, neither model completely accounts for the developmental differences found between singular and plural.

Acquiring diminutive allomorphs: taking item-specific characteristics into account

Phonological characteristics and frequencies of stems and allomorphs have been explored as possible factors causing differences in production accuracies between allomorphic forms. However, previous findings are not consistent and the relative contributions of these factors are unclear. This study investigated target and erroneous productions of the Dutch diminutive, which has five allomorphs with varying type frequencies and of which the selection depends on the phonological characteristics of the stems. Typically developing children (N = 115, 5;1-10;3) were tested on their production of real and nonce diminutives. Linear mixed effects modelling was used to analyse the data taking nonverbal IQ into account. Type frequencies of the allomorphs and differences in phonological characteristics of the stems were found to be related to differences in production accuracies between the allomorphs. However, phonological characteristics of the stems appeared to have a bigger impact, mainly due to the phonological complexity of these characteristics.

Realisation of grammatical morphemes by children with phonological impairment

The aim of this research was to explore how preschool-aged children with phonological impairment (PI) realise grammatical morphemes across different phonological contexts (i.e. singleton consonant, consonant cluster, syllable), conditions of finiteness and individual morpheme types. Factors accounting for children's realisation of grammatical morphemes were also examined. Eighty-seven Australian English-speaking preschoolers (aged 4-5 years) with PI completed the Children's Assessment of Morphophonology (CHAMP)-an elicited response task-in addition to standardised tests of speech and receptive language. The most challenging grammatical morphemes were finite morphemes (particularly past tense) and grammatical morphemes realised in consonant clusters. The ability to produce consonant clusters in single words significantly accounted for children's ability to realise grammatical morphemes, regardless of whether grammatical morphemes were realised in singleton, consonant cluster or syllable contexts. Realisation of grammatical morphemes by preschoolers with PI is influenced by phonological and morphological factors. The findings have implications regarding the assessment and differential diagnosis of preschoolers with concomitant phonological and language difficulties.

Comorbid morphological disorder apparent in some children aged 4-5 years with childhood apraxia of speech: findings from standardised testing

There is continuing debate about the origins of productive morphological errors in children with speech sound disorders. This is the case for children with theorised phonetic and motor disorders, such as children with childhood apraxia of speech (CAS, e.g., Ekelman & Aram, 1983; McNeill & Gillon, 2013 ). The morphological skills of children with CAS remain relatively unexplored in pre-schoolers. We investigated English morphology in a retrospective, cross-sectional design of 26 children aged 4-5 years who completed the Clinical Evaluation of Language Fundamentals-Preschool (2nd edition; Wiig, Secord & Semel, 2006). The research aims were to determine: (1) the language profile of the children, (2) the accuracy of each morpheme type produced, and (3) how many of those morphological errors are explained by speech errors (clusters, late developing phonemes, central vowels or weak syllable stress)? The results indicate the group of children with CAS had poorer expressive language skills than receptive skills and 48% demonstrated difficulties with morphology in word structure and recalling sentences subtests. The children had poor accuracy and inconsistent production of a range of morphemes and despite many errors due to the speech characteristics of the stimuli on the CELF-P2, motor speech concerns could not explain all the child's morphological errors. The results suggest morphological difficulties are co-morbid to CAS and when this occurs, treatment for morphosyntax is indicated. There are also significant clinical implications in the assessment of morphosyntax for children with CAS which are discussed.

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.

Phonological and morphophonological effects on grammatical development in children with specific language impairment

BACKGROUND

Five-year-olds with specific language impairment (SLI) often struggle with mastering grammatical morphemes. It has been proposed that verbal morphology is particularly problematic in this respect. Previous research has also shown that in young typically developing children grammatical markers appear later in more phonologically challenging contexts.

AIMS

The main aim was to explore whether grammatical deficits in children with SLI are morphosyntactic in nature, or whether phonological factors also explain some of the variability in morpheme production. The analysis considered the effects of the same phonological factors on the production of three different morphemes: two verbal (past tense -ed; third-person singular -s) and one nominal morpheme (possessive -s).

METHODS & PROCEDURES

The participants were 30 children with SLI (21 boys) aged 4;6-5;11 years (mean = 5;1). The data were collected during grammar test sessions, which consisted of question/answer elicitations of target forms involving picture props. A total of 2301 items were analysed using binary logistic regression; the predictors included: (1) utterance position of the target word, (2) phonological complexity of its coda, (3) voicing of the final stem consonant, (4) syllabicity (allomorph type) and (5) participant accounting for the individual differences in the responses.

OUTCOMES & RESULTS

The results showed a robust effect of syllabicity on the correct morpheme production. Specifically, syllabic allomorphs (e.g., She dresses) were significantly more challenging than the segmental ones (e.g., He runs) for all three morphemes. The effects of other factors were observed only for a single morpheme: coda complexity and voicing helped explain variability in past tense production, and utterance position significantly affected children's performance with the possessive. The participant factor also had a significant effect, indicating high within-group variability--often observed in SLI population.

CONCLUSIONS & IMPLICATIONS

The systematic effect of syllabicity across both verbal and nominal morphemes suggests morphophonological influences in the grammatical development of children with SLI that cannot be fully explained by syntactic deficits. Poorer performance in producing syllabic allomorphs can be accounted for by much lower overall frequency of these forms, and by the 'tongue-twisting' effect of producing similar segments in succession, as in added [aedəd], washes [wɒʃəz]. Interestingly, the greater acoustic salience of the syllabic allomorphs (an extra syllable) does not enhance children's abilities to produce them. These findings suggest that the interconnections between different levels of language have a stronger effect on the grammatical development of children with SLI than might be expected. Allomorphy should, therefore, be taken into account when designing language assessments and speech therapy, ensuring that children receive sufficient practice with the entire set of allomorphic variants.

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.

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.