F0 discontinuity as a marker of prosodic boundary strength in lombard speech

Prosodic boundary strength (PBS) refers to the degree of disjuncture between two chunks of speech. It is affected by both linguistic and para-linguistic communicative intentions playing thus an important role in both speech generation and recognition tasks. Among several PBS signals, we focus in this paper on pitch-related discontinuities in boundaries conveying linguistically meaningful contrasts produced in increasing levels of ambient noise. We compare several measures of local and global pitch reset and use classifiers in an effort to better understand the relationship between the degree of ambient noise and F0 marking of PBS. Our results include a positive effect of some noise on boundary classification, better performance of local than global reset features, and more systematic behavior of F0 falls compared to rises.