UC Berkeley

This dissertation tests the premise that, for beginning readers, speech is the ‘object of segmentation’ (Schreuder and van Bon, 1989). I posit that one aspect of speech in particular— coarticulation as proxied by gestural overlap—is likely to influence segmentation performance: reduced coarticulation should enable segmentation, while greater overlap should make it more difficult. Using empirical evidence of gestural overlap from articulatory Phonetics, I make predictions about the segmentability of English and Spanish stimuli, both between and within languages. Participants were 472 TK – Grade 2 children from various educational contexts. Students were asked to segment a spoken word. Their responses received two scores: first sound isolation (0/1) and unitization (0/1), the latter denoting instances where the first two phonemes of a stimulus were identified as a single unit (e.g., /fl/ for flee). For each outcome, 12,388 responses were analyzed within a Generalized Linear Mixed Model (GLMM) framework that controlled for item- and person-side variables. Five out of six hypotheses were supported, pointing to a strong, predictable association between gestural overlap and segmentation performance. Specifically: 1) English clusters were more difficult to segment than Spanish clusters; 2) English items starting with vowels followed by sonorants (e.g., eel) were more difficult than their Spanish counterparts and English equivalents with obstruent codas (e.g., eke); 3) English and Spanish singleton onsets did not differ in difficulty; 4) voiced-plosive clusters were more difficult than unvoiced-plosive clusters in both languages; 5) fricative clusters were easier to segment than plosive clusters in both languages.  Taken together, these results suggest that the speech code is indeed what participants operate on during a phoneme segmentation task. These findings are discussed within the context of broader literature on theory-development, reading instruction, and assessment.