Hearing the message and seeing the messenger: The role of talker information in spoken language comprehension

Abstract

The acoustic signal consists of various layers of information that we often process unconsciously. Most importantly, they contain both linguistic and indexical information, which are the two fundamental components within the sound input. Even though the meaning of the word does not change when spoken by multiple speakers, the same word never sounds exactly the same. That is because individuals introduce all kinds of variation to the speech input. Hence, through segmental and suprasegmental information, listeners can discern the nativeness (native vs. non-native) of the talker and the age of the talker (adult vs. child). Both non-native talkers and child talkers deviate from the standard norms of pronunciation of native adults and show variation both within and between talkers. The main difference between non-native adults and native children is that, for non-native talkers, variation is driven by their native language, meaning that the phonological structures of their native language interact with their second language; therefore, they maintain a foreign accent. For children, however, variation is driven by development, such that children's competencies in their motor skills depend on their current stage of language development. While there has been extensive research on foreign-accented speech, there is little knowledge about child speech. Especially the processing of child speech has only been investigated by a few studies so far. Hence, the central question of the dissertation is "What is the role of talker information in spoken language comprehension?" This question was investigated from three distinct angles: The first project examined talker information from an auditory-only perspective, the second project investigated talker information from an audio-visual perspective, and the third project studied the impact of talker information on listeners' credibility ratings in the socio-linguistic context.