In a series of experiments, the masked priming paradigm with very brief prime exposures was used to investigate the role of the syllable in the production of English. Experiment 1 (word naming task) showed a syllable priming effect for English words with clear initial syllable boundaries (such as BAL-CONY), but no effect with ambisyllabic words targets (such as BALANCE, where the /l/belongs to both the first and the second syllables). Experiment 2 failed to show such syllable priming effects in the lexical decision task. Experiment 3 demonstrated that for words with clear initial syllable boundaries, naming latencies were faster only when primes formed the first syllable of the target, in comparison with a neutral condition. Experiment 4 showed that the two possible initial syllables of ambisyllabic words facilitated word naming to the same extent, in comparison with the neutral condition. Finally, Experiment 5 demonstrated that the syllable priming effect obtained for CV words with clear initial syllable boundaries (such as DIVORCE) was not due to increased phonological and/or orthographic overlap. These results, showing that the syllable constitutes a unit of speech production in English, are discussed in relation to the model of phonological and phonetic encoding proposed by Levelt and Wheeldon (1994).What is the role of syllables in speech production? In a recent study, Ferrand, Segui, and Grainger (1996) demonstrated that French subjects responded faster in word-, nonword-, or picture-naming tasks when the prime corresponded to the first syllable of the stimulus than when it corresponded to a longer or a shorter segment than the first syllable. Each prime corresponded to a complete syllable only in one of the two words: BA was exactly the first syllable of the word BA.LADE,l but less than the first syllable of the word BAL.CON, whereas BAL was exactly the first syllable OfBAL.CON, but more than the first syllable of BA.LADE. Thus the word BA.LADE was named faster when preceded by the prime BA than by BAL, whereas the word BAL.CON was named faster when preceded by the prime BAL than by BA. These results provide evidence for the syllable as a fundamental unit of speech production in French and mirror those obtained in speech perception (Mehler, Frauenfelder, Dommergues, & Segui,The research reported in this article was partially supported by a postdoctoral grant (COGNISCIENCES) to L.F. from the Centre National delaRecherche Scientifique (C.N.R.S.) and byanEconomic and Social Research Council grant to G.W.H. A preliminary report of this study was presented at the European Summer School on "Aspects of Speech Production," held attheUniversity ofBirmingham, England, in July 1995. We thank Kathryn Spoehr, Arthur Samuel, Linda Wheeldon, Ardi Roelofs, and two anonymous reviewers for their comments onthis work. Address correspondence to 1. Ferrand, Laboratoire de Psychologie Experimentale, C.N.R.S. and Universite Rene Descartes, 28 rueSerpente, 75006 Paris, France (e-mail: ferrandl@idf.ext.jussieu.fr).1981; Segui, 1...