Abstract

Spoken language generally provides various levels of information for the interpretation of the incoming speech stream. Moreover, speech contains specific prosodic cues to indicate the presence of intonational phrase boundaries (IPB).

It has been shown that IPBs elicit a specific component in Auditory Evoked Potentials, the so-called closure-positive-shift (CPS; see Steinhauer, Alter & Friederici 1999, Pannekamp et al 2005). In this talk, I would like to discuss this issue in studies investigating brain responses to IPBs and accents.

Investigations of IPBs

Four experiments systematically investigating the brain’s response to the perception of sentences containing differing amounts of linguistic information will be presented. The focus is on the processing of IPBs with respect to syntactic, semantic, and phonemic information. Quasi-natural sentence material with decreasing semantic, syntactic, and phonemic information was created (i. e., jabberwocky sentences, in which all content words were replaced by meaningless words; pseudoword sentences, in which all function and all content words are replaced by meaningless words; and hummed sentences).

In this series of ERP investigations, the on-line brain responses to the processing of sentences containing a different number of IPBs (Pannekamp et al 2005) were recorded. It can be shown that the CPS relies primarily on prosodic information in the speech stream.

Investigations of accents

In a follow-up study ERP correlates for the processing of focal accents and their compatibility relative to a context question (information structure) has been investigated. ERP data suggest that in compatible answers, lexical elements carrying the respective accent elicit a centro-parietal positivity. The ERP patterns for incompatible answers appear to be more complex. Depending on both the type of violation and the position in the sentence we observed either a negative slow wave or a biphasic sequence of components. The nature of the ERPs will be discussed in the context of prosodic processing models taking into account the particular role of information structure in every-day conversation (Toepel et al 2007).