Functional Data Analysis of Tongue Profiles

We present in this work the functional data analysis of a data set of tongue profiles recorded for a study on Tyrolean, a German dialect spoken in South Tyrol . We test pairwise differences between five different manners of articulation of the uvular /R/: vocalized /R/, approximant , fricative, tap, and trill. The analysis is based on the Interval-Wise Testing ( IWT ), a non-parametric inferential procedure for functional data. The output of the IWT is an adjusted $p$ -value function that can be used to select intervals of the domain imputable for the rejection of a null hypothesis. IWT is jointly applied to the position, slope, and concavity of the tongue profiles. IWT -based comparisons result in an informative and detailed representation of the regions of the tongue where a significant difference is located.