An orthographic effect in phoneme processing, and its limitations

Testing for canonical form orientation in speech tempo perception

We report on two experiments that aimed to test the hypothesis that English listeners orient to full pronunciation forms-"canonical forms"-in judging the tempo of speech that features deletions. If listeners orient to canonical forms, this should mean that the perceived tempo of speech containing deletions is highly relative to the speech's articulation rate calculated on the basis of surface phone strings. We used controlled stimuli to test this hypothesis. We created sentences with one ambiguous word form (for example, support~sport), to give half of the listeners an orthographic form that includes support and the other half an otherwise identical orthographic form with sport. In both experiments, listeners judged the tempo of the sentences, which allowed us to assess whether the difference in imposed interpretation had an impact on perceived tempo. Experiment 1 used a tempo rating task in which listeners evaluated the tempo of experimental stimuli relative to comparison stimuli, on a continuous scale. Experiment 2 used a tempo comparison task in which listeners judged whether second members of stimulus pairs were slower or faster than first members. Both experiments revealed the predicted effect of the imposed word interpretation: sentences with an imposed "schwa" interpretation for the ambiguous word form were judged faster than (the same) sentences with an imposed "no schwa" interpretation. However, in both experiments the effect was small and variables related to the experimental design had significant effects on responses. We discuss the results' implications for our understanding of speech tempo perception.

Distinct orthography boosts morphophonological discrimination: Vowel raising in Bengali verb inflections

This study is concerned with how vowel alternation, in combination with and without orthographic reflection of the vowel change, affects lexical access and the discrimination of morphologically related forms. Bengali inflected verb forms provide an ideal test case, since present tense verb forms undergo phonologically conditioned, predictable vowel raising. The mid-to-high alternations, but not the low-to-mid ones, are represented in the orthography. This results in three different cases: items with no change (NoDiff), items with a phonological change not represented in the orthography (PronDiff) and items for which both phonology and orthography change (OrthPronDiff). To determine whether these three cases differ in terms of lexical access and discrimination, we conducted two experiments. Experiment 1 was a cross-modal lexical decision task with auditory primes (1stperson and 3rdperson forms, e.g. [lekhe] or [likhi]) and visual targets (verbal noun; e.g. [lekha]). Experiment 2 uses eye tracking in a fragment completion task, in which auditory fragments (first syllable of 1st or 3rdperson form, e.g. [le-] from [lekhe]) were to be matched to one of two visual targets (full 1st and 3rdperson forms, [lekhe] vs. [likhi] in Bengali script). While the lexical decision task, a global measure of lexical access, did not show a difference between the cases, the eye-tracking experiment revealed effects of both phonology and orthography. Discrimination accuracy in the OrthPronDiff condition (vowel alternation represented in the orthography) was high. In the PronDiff condition, where phonologically differing forms are represented by the same graphemes, manual responses were at chance, although eye movements revealed that match and non-match were discriminated. Thus, our results indicate that phonological alternations which are not represented in spelling are difficult to process, whereas having orthographically distinct forms boosts discrimination performance, implying orthographically influenced mental phonological representations.

Phonemic Training Modulates Early Speech Processing in Pre-reading Children

Phonemic awareness and rudimentary grapheme knowledge concurrently develop in pre-school age. In a training study, we tried to disentangle the role of both precursor functions of reading for spoken word recognition. Two groups of children exercised with phonemic materials, but only one of both groups learnt corresponding letters to trained phonemes. A control group exercised finger-number associations (non-linguistic training). After the training, we tested how sensitive children were to prime-target variation in word onset priming. A group of young adults took part in the same experiment to provide data from experienced readers. While decision latencies to the targets suggested fine-grained spoken word processing in all groups, event-related potentials (ERPs) indicated that both phonemic training groups processed phonemic variation in more detail than the non-linguistic training group and young adults at early stages of speech processing. Our results indicate temporal plasticity of implicit speech processing in pre-school age as a function of explicit phonemic training.

The Influence of Orthography on Phonemic Knowledge: An Experimental Investigation on German and Persian

This study investigated whether the phonological representation of a word is modulated by its orthographic representation in case of a mismatch between the two representations. Such a mismatch is found in Persian, where short vowels are represented phonemically but not orthographically. Persian adult literates, Persian adult illiterates, and German adult literates were presented with two auditory tasks, an AX-discrimination task and a reversal task. We assumed that if orthographic representations influence phonological representations, Persian literates should perform worse than Persian illiterates or German literates on items with short vowels in these tasks. The results of the discrimination tasks showed that Persian literates and illiterates as well as German literates were approximately equally competent in discriminating short vowels in Persian words and pseudowords. Persian literates did not well discriminate German words containing phonemes that differed only in vowel length. German literates performed relatively poorly in discriminating German homographic words that differed only in vowel length. Persian illiterates were unable to perform the reversal task in Persian. The results of the other two participant groups in the reversal task showed the predicted poorer performance of Persian literates on Persian items containing short vowels compared to items containing long vowels only. German literates did not show this effect in German. Our results suggest two distinct effects of orthography on phonemic representations: whereas the lack of orthographic representations seems to affect phonemic awareness, homography seems to affect the discriminability of phonemic representations.

How much does orthography influence the processing of reduced word forms? Evidence from novel-word learning about French schwa deletion

This study examines the influence of orthography on the processing of reduced word forms. For this purpose, we compared the impact of phonological variation with the impact of spelling-sound consistency on the processing of words that may be produced with or without the vowel schwa. Participants learnt novel French words in which the vowel schwa was present or absent in the first syllable. In Experiment 1, the words were consistently produced without schwa or produced in a variable manner (i.e., sometimes produced with and sometimes produced without schwa). In Experiment 2, words were always produced in a consistent manner, but an orthographic exposure phase was included in which words that were produced without schwa were either spelled with or without the letter <e>. Results from naming and eye-tracking tasks suggest that both phonological variation and spelling-sound consistency influence the processing of spoken novel words. However, the influence of phonological variation outweighs the effect of spelling-sound consistency. Our findings therefore suggest that the influence of orthography on the processing of reduced word forms is relatively small.

Orthographic effects in spoken word recognition: Evidence from Chinese

Extensive evidence from alphabetic languages demonstrates a role of orthography in the processing of spoken words. Because alphabetic systems explicitly code speech sounds, such effects are perhaps not surprising. However, it is less clear whether orthographic codes are involuntarily accessed from spoken words in languages with non-alphabetic systems, in which the sound-spelling correspondence is largely arbitrary. We investigated the role of orthography via a semantic relatedness judgment task: native Mandarin speakers judged whether or not spoken word pairs were related in meaning. Word pairs were either semantically related, orthographically related, or unrelated. Results showed that relatedness judgments were made faster for word pairs that were semantically related than for unrelated word pairs. Critically, orthographic overlap on semantically unrelated word pairs induced a significant increase in response latencies. These findings indicate that orthographic information is involuntarily accessed in spoken-word recognition, even in a non-alphabetic language such as Chinese.

Unattentive speech processing is influenced by orthographic knowledge: evidence from mismatch negativity

How far can acquired knowledge such as orthographic knowledge affect pre-existing abilities such as speech perception? This controversial issue was addressed by investigating the automaticity of the influence of orthographic knowledge on speech processing. Many studies demonstrated this influence in active, lexico-semantic speech processing tasks. However, it has never been observed when speech is unattended. Here, the Mismatch Negativity (MMN), an automatic index of experience-dependent auditory traces, was recorded in an unattended oddball paradigm manipulating the orthographic congruency between frequent and deviant spoken riming words. Both orthographically congruent and incongruent deviant words elicited a typical MMN over the fronto-central regions, with a stronger response in the incongruent condition. The finding showed that the orthographic dimension of spoken words influences a physiological marker of speech processing although participants were required not to attend to the auditory input. This provides evidence for an impact of acquiring a written code on speech processing.