Neural Representation of the English Vowel Feature [High]: Evidence From /ε/ vs. /ɪ/

Many studies have observed modulation of the amplitude of the neural index mismatch negativity (MMN) related to which member of a phoneme contrast [phoneme A, phoneme B] serves as the frequent (standard) and which serves as the infrequent (deviant) stimulus (i.e., AAAB vs. BBBA) in an oddball paradigm. Explanations for this amplitude modulation range from acoustic to linguistic factors. We tested whether exchanging the role of the mid vowel /ε/ vs. high vowel /ɪ/ of English modulated MMN amplitude and whether the pattern of modulation was compatible with an underspecification account, in which the underspecified height values are [−high] and [−low]. MMN was larger for /ε/ as the deviant, but only when compared across conditions to itself as the standard. For the within-condition comparison, MMN was larger to /ɪ/ deviant minus /ε/ standard than to the reverse. A condition order effect was also observed. MMN amplitude was smaller to the deviant stimulus if it had previously served as the standard. In addition, the amplitudes of late discriminative negativity (LDN) showed similar asymmetry. LDN was larger for deviant /ε/ than deviant /ɪ/ when compared to themselves as the standard. These findings were compatible with an underspecification account, but also with other accounts, such as the Natural Referent Vowel model and a prototype model; we also suggest that non-linguistic factors need to be carefully considered as additional sources of speech processing asymmetries.

Phonological Underspecification: An Explanation for How a Rake Can Become Awake

Neural markers, such as the mismatch negativity (MMN), have been used to examine the phonological underspecification of English feature contrasts using the Featurally Underspecified Lexicon (FUL) model. However, neural indices have not been examined within the approximant phoneme class, even though there is evidence suggesting processing asymmetries between liquid (e.g., /ɹ/) and glide (e.g., /w/) phonemes. The goal of this study was to determine whether glide phonemes elicit electrophysiological asymmetries related to [consonantal] underspecification when contrasted with liquid phonemes in adult English speakers. Specifically, /ɹɑ/ is categorized as [+consonantal] while /wɑ/ is not specified [i.e., (–consonantal)]. Following the FUL framework, if /w/ is less specified than /ɹ/, the former phoneme should elicit a larger MMN response than the latter phoneme. Fifteen English-speaking adults were presented with two syllables, /ɹɑ/ and /wɑ/, in an event-related potential (ERP) oddball paradigm in which both syllables served as the standard and deviant stimulus in opposite stimulus sets. Three types of analyses were used: (1) traditional mean amplitude measurements; (2) cluster-based permutation analyses; and (3) event-related spectral perturbation (ERSP) analyses. The less specified /wɑ/ elicited a large MMN, while a much smaller MMN was elicited by the more specified /ɹɑ/. In the standard and deviant ERP waveforms, /wɑ/ elicited a significantly larger negative response than did /ɹɑ/. Theta activity elicited by /ɹɑ/ was significantly greater than that elicited by /wɑ/ in the 100–300 ms time window. Also, low gamma activation was significantly lower for /ɹɑ/ vs. /wɑ/ deviants over the left hemisphere, as compared to the right, in the 100–150 ms window. These outcomes suggest that the [consonantal] feature follows the underspecification predictions of FUL previously tested with the place of articulation and voicing features. Thus, this study provides new evidence for phonological underspecification. Moreover, as neural oscillation patterns have not previously been discussed in the underspecification literature, the ERSP analyses identified potential new indices of phonological underspecification.

Explaining Cross-Language Asymmetries in Prosodic Processing: The Cue-Driven Window Length Hypothesis

Cross-language studies have shown that English speakers use suprasegmental cues to lexical stress less consistently than speakers of Spanish and other Germanic languages ; accordingly, these studies have attributed this asymmetry to a possible trade-off between the use of vowel reduction and suprasegmental cues in lexical access. We put forward the hypothesis that this “cue trade-off” modulates intonation processing as well, so that English speakers make less use of suprasegmental cues in comparison to Spanish speakers when processing intonation in utterances causing processing asymmetries between these two languages. In three cross-language experiments comparing English and Spanish speakers’ prediction of hypo-articulated utterances in focal sentences and reporting speech, we have provided evidence for our hypothesis and proposed a mechanism, the Cue-Driven Window Length model, which accounts for the observed cross-language processing asymmetries between English and Spanish at both lexical and utterance levels. Altogether, results from these experiments illustrated in detail how different types of low-level acoustic information (e.g., vowel reduction versus duration) interacted with higher-level expectations based on the speakers’ knowledge of intonation providing support for our hypothesis. These interactions were coherent with an active model of speech perception that entailed real-time adjusting to feedback and to information from the context, challenging more traditional models that consider speech perception as a passive, bottom-up pattern-matching process.

Production and processing asymmetries in the acquisition of tense morphology by sequential bilingual children

This study investigates the production and online processing of English tense morphemes by sequential bilingual (L2) Turkish-speaking children with more than three years of exposure to English. Thirty-nine six- to nine-year-old L2 children and twenty-eight typically developing age-matched monolingual (L1) children were administered the production component for third person -s and past tense of the Test for Early Grammatical Impairment (Rice & Wexler, 2001) and participated in an online word monitoring task involving grammatical and ungrammatical sentences with presence/omission of tense (third person -s, past tense -ed) and non-tense (progressive -ing, possessive 's) morphemes. The L2 children's performance on the online task was compared to that of children with Specific Language Impairment (SLI) in Montgomery and Leonard (1998, 2006) to ascertain similarities and differences between the two populations. Results showed that the L2 children were sensitive to the ungrammaticality induced by the omission of tense morphemes, despite variable production. This reinforces the claim about intact underlying syntactic representations in child L2 acquisition despite non-target-like production (Haznedar & Schwartz, 1997).