Explanation:
I'm pretty sure when there talking about the letters such as abba, cdc ect, there talking about rhyming so for the sentence "the frog sits on the log" it would be aa, basically if the rhyming words go bread duck head truck, in a sentence the first rhyming word would be a and the second would be b, so u would say it's abab, I hope that makes sense, sorry if it doesn't lol
