People heard a cough or a tone replace the first "s" in the word legislatures. what conclusion did the result support?

I Believe the answer is: We perceive a word as a whole, not as separate letters.

When we heard other people spouting out words in order to send a certain message, our brain would not pay attention too much on each single letter that exist, but put more focus on the overall/whole meaning of the words to decipher the core message within it.