Abstract The ultimate test of the adequacy of linguistic models of fluency breakdown is the degree to which they may account for patterns of dysfluency in the speech of a stutterer who is fluent in more than one language. We present the case of an adult bilingual stutterer (Spanish-English), whose spontaneous language in both Spanish and English was structurally analyzed to assess the relationships of phonological and syntactic structure to the frequency and location of fluency breakdown. Our findings suggest that syntax is probably a greater determinant of stuttered moments than is phonology. Additionally, similarities and differences between English and Spanish sentence structure were associated with similarities and differences in the loci of dysfluencies across the two languages. The need for crosslinguistic research utilizing monolingual and bilingual speakers of languages other than English is emphasized.