What is the role of timing in on-line speech processing?

Quite a lot of research has focused on the way in which we recognise differences in the quality of segments in the acoustic stream, and relate these to abstract phonological representations. Less work, however, has investigated the role of temporal information in the endeavour of identifying phonemes and, from there, syllables and words.

In languages which encode a phonological contrast in consonant length, both identifying phonemes and building syllable structure depend on the extraction of durational information from the speech stream. My Master’s thesis (under the supervision of Aditi Lahiri at the Language and Brain Lab, University of Oxford) investigated the interaction between these two aspects of durational processing in lexical access in Swiss German using the N400, an electrophysiological component which offers a fine-grained measure of the success of lexical processing. In Swiss German, consonant duration is the primary cue to a segment’s geminate or singleton identity, and simultaneously indicates a divergence in syllable structure (CV.CV for singletons, CVC.CV for geminates). In our cross-modal semantic priming study, we tested whether words with phonetically distorted consonant duration (and therefore, an incorrect syllable structure) could trigger lexical access. Participants heard words whose medial consonant duration had been manipulated such that singletons were presented with geminate duration, and vice versa. Behavioural and ERP results revealed a processing asymmetry: adding durational information to a singleton does not disrupt lexical access, but subtracting it from a geminate does. We argue that abstract syllable structure plays a decisive role in lexical access in length-contrastive phonological systems, and that the observed processing asymmetry indicates a bias towards initially parsing acoustic input into CV syllables.

Publications and Presentations

Ehrenhofer, Lara, Roberts, A. C., Wetterlin, A., Kotzor, S. and Lahiri, A. Asymmetric processing of consonant duration in Swiss German. In Kuzobono, Haruo (ed.), Phonetics and Phonology of Geminate Consonants, Oxford Studies in Phonetics and Phonology, Oxford, UK: Oxford University Press. Expected publication date: May 2017!

Ehrenhofer, Lara. “When Less is Not Enough: Parsing Consonant Duration in Swiss German.” Language Science Lunch Talks series, University of Maryland, College Park, 2 October 2014.

Ehrenhofer, Lara, A. C. Roberts, A. Wetterlin, S. Kotzor and A. Lahiri. “When Less is Not Enough: Processing Variation in Geminate Duration in Swiss German.” Presented at the 2014 Annual Meeting of the Linguistics Association of Great Britain, Queen’s College, Oxford, 1-5 September 2014.

Ehrenhofer, Lara. “Processing of medial geminate and singleton consonants in Swiss German: behavioural and ERP evidence.” MPhil thesis, University of Oxford (2013). Download here.