Uncovering Tonal and Temporal Correlates of Phrasal Prominence in Medʉmba

Characterizing prosodic prominence relations in African tone languages is notoriously difficult, as typical acoustic cues to prominence (changes in F0, increases in intensity, etc.) can be difficult to distinguish from those which mark tonal contrasts. The task of establishing prominence is further complicated by the fact that tone, an important cue to syllable prominence and prosodic boundaries cross-linguistically, plays many roles in African languages: tones often signal lexical contrasts, can themselves be morphemes, and can also interact in key ways with prosody. The present study builds on phonological generalizations about tonal patterns in Medʉmba, a Grassfields Bantu language, and uses the speech cycling paradigm to investigate relative timing of syllables varying in phrase-level prominence. Specifically, we investigate timing asymmetries between syllables hypothesized to occur at the edge of a phonological phrase, which carry a high phrase accent, and those in phrase-medial position, which do not. Results indicate significant differences in the temporal alignment of accented versus non-accented syllables, with accented syllables occurring significantly closer to positions established as prominence-attracting in previous speech cycling research. We show that these findings cannot be attributed to differences in tone alone. Findings demonstrate the importance of relative temporal alignment as a correlate of prosodic prominence. Findings also point to increased duration as a phonetic property which distinguishes between syllables bearing phrasal prominence from those which do not.