Exploring the phrase-internal changes in articulation rate: the LARometer tool and its applications

The article introduces a method of normalising the inherent durational properties of phones (the LARometer), providing a relative measure of local articulation rate (LAR). It allows for the quantification of the communicatively relevant variations in articulation rate and their visualisation in temporal contours. The normalisation is based on an extensive manually annotated corpus containing over four hours of continuous speech. The usage of the LARometer is illustrated with two studies. Study 1 identifies locally decelerated content words in Czech radio news reading. These decelerated words often had prominent functions in the information structure (rheme, contrastive topic). The results also indicated that deceleration affects various parts of words. Study 2 focuses on phone reductions in television political debates. The reductions were predominantly observed in content words, but function words were affected to greater extent. Also, considerable differences in the number of reductions were found between individual speakers.