Trying out Praat with Butter on a Cot

After learning how to use Praat in class, I was ready to experiment with accents and compare spectrograms. I thought that the way our accents could be manifested in series of up and down squiggly lines was awesome.
I first began with my "natural" accent, a Midwest one I guess, and said "The butter spilled on the cot" to the computer. I seemed to say "butter" with a "d" sound as opposed an actual "t". Also, I said "cot" in the same way I say "caught". Also, I said "spilled" with an "eh" short vowel sound. In general, I thought I was speaking at an average pace.
Then I attempted a Southern accent, or what I thought sounded like a southern accent. I added a sort of drawl to the words. For example, I extended the "uh" sound in "butter". Also, instead of hearing the "eh" sound in spilled, I used more of an "ee" sound, but not quite. The word cot sounded different, although I'm not quite sure how to explain the difference. In general, I noticed that I spoke a bit slower.
These differences could easily be seen in the spectrograms of the different accents. My natural accent had much shorter wavelengths. The wavelengths of the southern accent were about twice as long. I'm assuming this is a result of my attempt at a drawl. The basic pattern and location of the words is generally the same, the southern one is just more spread out. This might mean I didn't do a very good job trying to distinguish the southern accent.
Perhaps next time the differences in my spectrograms will be more distinct. Overall, this task was fun. I even went around asking random people in my dorm to say "the butter spilled on the cot" and I notice differences. A New Yorker said it way different than a girl from Wisconsin. Perhaps next time I'll ask themselves to speak into the computer for Praat to compare spectrograms.