It is a well-known fact that across the world’s languages there is a fairly strong asymmetry in the affixation of grammatical material, in that suffixes considerably outnumber prefixes in typological databases. This article argues that prosody, specifically prosodic phrasing, plays an important part in bringing about this asymmetry. Prosodic word and phrase boundaries may occur after a clitic function word preceding its lexical host with sufficient frequency so as to impede the fusion required for affixhood. Conversely, prosodic boundaries rarely, if ever, occur between a lexical host and a clitic function word following it. Hence, prosody does not impede the fusion process between lexical hosts and postposed function words, which therefore become affixes more easily.
Evidence for the asymmetry in prosodic phrasing is provided from two sources: disfluencies, and ditropic cliticization, that is, the fact that grammatical proclitics may be phonological enclitics (i.e. phrased with a preceding host), but grammatical enclitics are never phonological proclitics. Earlier explanations for the suffixing preference have neglected prosody almost completely and thus also missed the related asymmetry in ditropic cliticization. More importantly, the evidence from prosodic phrasing suggests a new venue for explaining the suffixing preference. The asymmetry in prosodic phrasing, which, according to the hypothesis proposed here, is a major factor underlying the suffixing preference, has a natural basis in the mechanics of turn-taking as well as in the mechanics of speech production.*