# Problem getting DTW to work for speech recognition

I used my ipad to record the words "This. Is. A. Test. This. Is. A. Test.", then downloaded it to my computer as a .MOV file and used ffmpeg to extract audio as WAV. I then used the tuneR package to load the WAV file into R.

library(tuneR)
plot(sndObj@left, type = "l")


It loads fine and the plot looks ok. The problem comes when I segment the words and calculate DTW distances between all pairs of words (using the DTW package in R).

I can't find any evidence that DTW distance is smaller between the correct pairs than between any other pairing (i.e "this->this" is about the same DTW distance as "this->a". Am I missing any important preprocessing?

Below: sample heat map of actual vs expected DTW distances.