Difficulties in decoupling articulatory gestures in L2 phonemic sequences: the case of Mandarin listeners' perceptual deletion of English post-vocalic laterals.

Nonnative or second language (L2) perception of segmental sequences is often characterised by perceptual modification processes, which may "repair" a nonnative sequence that is phonotactically illegal in the listeners' native language (L1) by transforming the sequence into a sequence that is phonotactically legal in the L1. Often repairs involve the insertion of phonetic materials (epenthesis), but we focus, here, on the less-studied phenomenon of perceptual deletion of nonnative phonemes by testing L1 Mandarin listeners' perception of post-vocalic laterals in L2 English using the triangulating methods of a cross-language goodness rating task, an AXB task, and an AX task. The data were analysed in the framework of the Perceptual Assimilation Model (PAM/PAM-L2), and we further investigated the role of L2 vocabulary size on task performance. The experiments indicate that perceptual deletion occurs when the post-vocalic lateral overlaps with the nucleus vowel in terms of tongue backness specification. In addition, Mandarin listeners' discrimination performance in some contexts was significantly correlated with their English vocabulary size, indicating that continuous growth of vocabulary knowledge can drive perceptual learning of novel L2 segmental sequences and phonotactic structures.

Two-part vowel modifications in Child Directed Speech in Warlpiri may enhance child attention to speech and scaffold noun acquisition.

Study 1 compared vowels in Child Directed Speech (CDS; child ages 25-46 months) to vowels in Adult Directed Speech (ADS) in natural conversation in the Australian Indigenous language Warlpiri, which has three vowels (/i/, /a/, /u). Study 2 compared the vowels of the child interlocutors from Study 1 to caregiver ADS and CDS. Study 1 indicates that Warlpiri CDS vowels are characterised by fronting, /a/-lowering, f o -raising, and increased duration, but not vowel space expansion. Vowels in CDS nouns, however, show increased between-contrast differentiation and reduced within-contrast variation, similar to what has been reported for other languages. We argue that this two-part CDS modification process serves a dual purpose: Vowel space shifting induces IDS/CDS that sounds more child-like, which may enhance child attention to speech, while increased between-contrast differentiation and reduced within-contrast variation in nouns may serve didactic purposes by providing high-quality information about lexical specifications. Study 2 indicates that Warlpiri CDS vowels are more like child vowels, providing indirect evidence that aspects of CDS may serve non-linguistic purposes simultaneously with other aspects serving linguistic-didactic purposes. The studies have novel implications for the way CDS vowel modifications are considered and highlight the necessity of naturalistic data collection, novel analyses, and typological diversity.

Stop contrast acquisition in child Kriol: Evidence of stable transmission of phonology post Creole formation.

Many Aboriginal Australian communities are undergoing language shift from traditional Indigenous languages to contact varieties such as Kriol, an English-lexified Creole. Kriol is reportedly characterised by lexical items with highly variable phonological specifications, and variable implementation of voicing and manner contrasts in obstruents (Sandefur, 1986). A language, such as Kriol, characterised by this unusual degree of variability presents Kriol-acquiring children with a potentially difficult language-learning task, and one which challenges the prevalent theories of acquisition. To examine stop consonant acquisition in this unusual language environment, we present a study of Kriol stop and affricate production, followed by a mispronunciation detection study, with Kriol-speaking children (ages 4-7) from a Northern Territory community where Kriol is the lingua franca. In contrast to previous claims, the results suggest that Kriol-speaking children acquire a stable phonology and lexemes with canonical phonemic specifications, and that English experience would not appear to induce this stability.

Voice onset time and constriction duration in Warlpiri stops (Australia).

This paper presents a first detailed analysis of the Voice Onset Time (VOT) and Constriction Duration (CD) of stops /p t ʈ c k/ and flap /ɽ/ in the Indigenous Australian language Warlpiri as spoken in Lajamanu Community, in Australia's Northern Territory. The results show that Warlpiri stops are realised as voiceless, long-lag stops word-initially, as well as word-medially, where /p t k/ are also characterised by CDs in excess of 100 ms. This is similar to what has been reported for Kriol, and for the emerging mixed language Light Warlpiri, also spoken in the community, and by some of the participants. The results indicate that Warlpiri does not obligatorily make a word-medial distinction between stops orthographically represented by 'rt' and 'rd', which have previously been argued to be realised as /ʈ/ and /ɽ/, respectively, at least in some varieties of Warlpiri. Finally, the results also suggest that the realisation of word-initial Warlpiri flap /ɽ/ is highly variable, potentially resulting in a near-merger with /É»/.

Consonantal timing and release burst acoustics distinguish multiple coronal stop place distinctions in Wubuy (Australia).

Substantial research has established that place of articulation of stop consonants (labial, alveolar, velar) are reliably differentiated using a number of acoustic measures such as closure duration, voice onset time (VOT), and spectral measures such as centre of gravity and the relative energy distribution in the mid-to-high spectral range of the burst. It is unclear, however, whether such measurable acoustic differences are present in multiple place of articulation contrasts among coronal stops. This article presents evidence from the highly endangered indigenous Australian language Wubuy, which maintains a 4-way coronal stop place contrast series in all word positions. The authors examine the temporal and burst characteristics of / t̪ t ʈ/ in three prosodic positions (utterance-initial, word-initial but phrase medial, and word-medial). The results indicate that VOT, closure duration, and the spectral quality of the burst may indeed differentiate multiple coronal place contrasts, in most positions, although measures that distinguish the apical contrast in absolute initial position remain elusive. The authors also examine measures (spectrum kurtosis, spectral tilt) previously used in other studies of multiple coronals in Australian languages. These results suggest that the authors' measures perform at least as well as those previously applied to multiple coronals in other Australian languages.

Pause acceptability indicates word-internal structure in Wubuy.

Words in polysynthetic languages, such as the Australian language Wubuy, can be semantically complex and translate into whole phrases in analytic languages such as English. This raises questions about whether such words are like words in English, or whether they are more like phrases. In the following, we examine Wubuy speakers' knowledge of word-internal morphological complexity in a word-preference task, in which we test the acceptability of complex words into which artificial pauses have been embedded at a range of morphological junctures. The results show that participants prefer unmodified words and words with pauses inserted at semantically transparent morphological junctures over words with pauses at other junctures. There is no preference for unmodified words over words with pauses at transparent junctures. These results suggest that speakers have access to some word-internal morphological information, and that complex words may share characteristics of both words and phrases in, for instance, English.

Discrimination of Multiple Coronal Stop Contrasts in Wubuy (Australia): A Natural Referent Consonant Account.

Native speech perception is generally assumed to be highly efficient and accurate. Very little research has, however, directly examined the limitations of native perception, especially for contrasts that are only minimally differentiated acoustically and articulatorily. Here, we demonstrate that native speech perception may indeed be more difficult than is often assumed, where phonemes are highly similar, and we address the nature and extremes of consonant perception. We present two studies of native and non-native (English) perception of the acoustically and articulatorily similar four-way coronal stop contrast /t ʈ [symbol: see text] ȶ/ (apico-alveolar, apico-retroflex, lamino-dental, lamino-alveopalatal) of Wubuy, an indigenous language of Australia. The results show that all listeners find contrasts involving /ȶ/ easy to discriminate, but that, for both groups, contrasts involving /t ʈ [symbol: see text]/ are much harder. Where the two groups differ, the results largely reflect native language (Wubuy vs English) attunement as predicted by the Perceptual Assimilation Model. We also observe striking perceptual asymmetries in the native listeners' perception of contrasts involving the latter three stops, likely due to the differences in input frequency. Such asymmetries have not previously been observed in adults, and we propose a novel Natural Referent Consonant Hypothesis to account for the results.