Acoustic correlates of flaps in North American English

Abstract

Using B/M mode ultrasound, Derrick & Gick (2010) identified four categorical variations of flaps in North American English, up-flaps, down-flaps, alveolar taps, and postalveolar taps produced in English. These variants can be used to test hypotheses about constraints on speech articulation, such as local context, gravity and elasticity, speech rate, and longer distance anticipatory coarticulation. This study examines acoustic correlates of flap variations in order to make connections between the results of larger, and easier to collect, acoustic databases and the tongue movements underlying flap productions. Preliminary analyses using smoothing spline ANOVAs of z-score normalized f0, F1, F2, F3, F4 and F5 indicate significant differences in each dependent variable for flaps in non-rhotic vowel contexts. The results for flaps adjacent to rhotic vowels is more complex, requiring more detailed analysis. Based on these results, we are currently planning supervised hierarchical clustering to aid in probabilistic identification of flap variants, with reference to both vocalic context and syllable structure. © 2013 Acoustical Society of America.