had, hid, head, etc.

I really enjoyed working on this assignment. After recording the various words (carefully making a distinction between "hod" and "hawed," which I might normally pronounce the same), I used Praat's formant listing tool to get the frequencies of the first and second formants. When I graphed the results, the graph was shaped like Figure 8.7, but there were a few differences. First, my graph was shifted left and down because my frequencies were higher than the example's. I assume this is because the example was based on a recording of a man. Second, my "hood" and "hid" were closer together in F2 pitch. The same thing happened with "heed" and "who'd." I was wondering if this had to do with the Southern shift we studied or if it is something else altogether.