The distribution of the duration of the 4185 schwas (fig.2) is divided into 2 sub-groups :

1. (1) Figure 2: Distribution of the schwa durations gap (2) Nb of occurrences Schwa duration ON THE CATEGORICAL NATURE OF THE PROCESS INVOLVED IN SCHWA ELISION IN FRENCHA. Bürki¹², C. Fougeron¹ & C. Gendrot¹ ¹Laboratoire de Phonétique et Phonologie, UMR 7018, CNRS-Paris 3/Sorbonne Nouvelle, France²Laboratoire de Psycholinguistique Expérimentale, Université de Genève, Suisse I. INTRODUCTION Research question: Does the realizations of schwa follow a continuous pattern of reduction ranging from a full vowel realization to a fully absent vowel, or do two categories emerge: full vowels on one side, and completely deleted vowels on the other side? • Prediction fora categorical alternation process: bimodal distribution of the schwa durations, with a gap between 2 groups (schwa-full and schwa-less forms). • Prediction for a gradual reduction process: continuous distribution towards 0 duration(i.e. schwa-less form = end-point of the gradual reduction process). Schwa elision in French = alternation between 2 variants of a same lexical entry with or without its schwa, e.g. ‘fenêtre’ (window) pronounced either with a schwa-full form [ft] or with a schwa-less form [ft] . Traditional phonological accounts assume that this alternation process is complete and results from a rule-based segmental process. Aim:determining whether experimental evidence can be found to assess the categorical nature of this process by analyzing the different realizations of words containing a schwa in the ESTER corpus (Galliano & al., 2005). II. METHOD (1) Creation of a repertory of 18553 French words containing a schwa. (2) Selection of words recognized by the IRISA automatic recognition system as being produced in the corpus in their schwa-less and schwa-full forms. (3) Manual examination and correction of the output of the automatic recognition system. Criteria for determining the presence/duration of schwa: - Realized schwa: voiced portion + formant structure - Onset and offset of the vowels: determined on signal periodicity and apparition / disappearance of F2 (Figure 1). (4)Analysis of the schwa durations of these words Figure 1: Schwa-full occurrence of the word ‘semaine’ (week). Manual segmentation according to the determined criteria. III. RESULTS The distribution of the duration of the 4185 schwas (fig.2) is divided into 2 sub-groups: (1) 29% of the words produced with a complete absence of voicing & formant structure, i.e. forms realized without a vocalic portion (e.g. fig. 3) (2) 71% of the occurrences present a vocalic portion corresponding to a schwa, i.e. forms realized with a vocalic portion (e.g. fig. 4). (The distribution of the duration of these schwa-full forms is unimodal and close to normality.) The distribution of schwa duration is not continuous but present a gap in the distribution between 0 and 16 ms. The distribution of the duration of the 4185 schwas (fig.2) is divided into 2 sub-groups: (1) 29% of the words produced with a complete absence of voicing & formant structure, i.e. forms realized without a vocalic portion (e.g. fig. 3) (2) 71% of the occurrences present a vocalic portion corresponding to a schwa, i.e. forms realized with a vocalic portion (e.g. fig. 4). (The distribution of the duration of these schwa-full forms is unimodal and close to normality.) The distribution of schwa duration is not continuous but present a gap in the distribution between 0 and 16 ms. Figure 3 and 4: Schwa-less (left) and schwa-full (right) occurrences of the word ‘sera’ (will be). IV. DISCUSSION AND CONCLUSION IV. DISCUSSION AND CONCLUSION • The bimodal distribution seems to support the categorical nature of the process. • However, the gap between the two groups could be a by-product of the criteriachosen to define the acoustical interval corresponding to schwa. Nonetheless, modifying our segmentation criteria to include realizationssuch as fig. 5would not have changed the distribution to support a continuous gradual process. (If realizations such as fig. 5 were categorized as schwa-full, it would not inflate the distribution in the gap region, but rather the left tail of group 2.) Interpretation :The distribution of schwa duration is explained by both a categorical and a gradual process. • a phonological categorical alternation process accounts for the leftmost mode of the distributionand the gapbetween the 2 groups. • a gradual phonetic process of reductionaccounts for the gradual temporal reductionwithin the rightmost group of the schwa-full forms. A thorough analysis of the 1215 occurrences included in the leftmost mode (categorized as schwa-less) is needed to confirm our interpretation. Figure 5: Realization of the word ‘avenir’ (future). The portion of increased intensity between [v] and [n] (25ms) could be attributed to a devoiced vowel.