Clear speech and phonological typology: A case study of Tashlhiyt Berber

Clear speech is a type of listener-oriented, intelligibility-enhancing mode of speaking. It has been shown to enhance the perceptibility of many different types of phonological contrasts, cross-linguistically. An open question is whether all phonological contrasts are enhanced to an equivalent extent in clear speech. In the current study, we ask whether rarer phonological patterns receive less of a clear speech intelligibility boost, relative to more common phoneme contrasts. Tashlhiyt Berber is an Afroasiatic language spoken in Morocco. Tashlhiyt has been well studied for having typologically uncommon phonotactic properties. This study examines the effect of clear speech on the discrimination of rarer lexical contrasts in Tashlhiyt Berber. We predict that the more typologically uncommon contrasts (e.g., word pairs containing complex and geminate initial onsets) will have a smaller increase in perceptibility from casual to clear speech than more common contrasts (e.g., singleton contrasts). Furthermore, native and naive listeners’ (here, American English speakers) discrimination of these contrasts across speech styles is also compared. Cross-language perception of clear speech provides a window to understanding the phonetic bases for cross-linguistic typological patterns.