We tested the hypothesis that a rough syntactic analysis can be performed by relying on phrasal prosody and function words. We used jabberwocky sentences in which prosodic cues and function words were preserved, but all content words were replaced by non-words. French adults managed to perform an abstract word detection task (targets specified with their syntactic category) on these sentences. We interpret these results as showing that phrasal prosody and function words allow listeners to start building a syntactic structure of spoken nonsense sentences. Adults were able to use phonological phrase boundaries to delimit syntactic constituents, and function words to label these constituents. Implications for language acquisition are discussed.