"The Butter Spilled on the Cot" analysis

The first time I recorded myself, I spoke in the way that I would say "The Butter Spilled on the Cot" in an everyday situation. The second time, I accented u in butter and the o in cot. I tried to make both of them sound more like the a in Alex. The differences in the spectogram are very interesting. For the word butter, both times there was an apparent stop in the middle of the word at the "tt". When I said it naturally, the amplitudes of the first and second syllables were very similar. When I implemented the accent and tried to make the u sound more like the a in Alex, the amplitude of the first syllable was much larger than that of the second. The rest of the spectogram of when I spoke naturally has pretty steady amplitudes, rising and falling numerous times throughout the rest of the sentence. On the spectogram of me speaking with the accent, though, there is a very low amplitude until I get to the word cot, where it suddenly peaks again and the lines become much larger and closer together.