Crosstalk is when you try to listen to someone talking, but you can hear someone else talking too. This can be really confusing and make it hard to understand what the person you want to listen to is saying.
American speech music is a special way of speaking that some people use, where they make their voices go up and down in pitch and change how loud or quiet they are talking. This can make what they're saying sound more interesting and help them get their point across better.
So, when there's crosstalk happening with American speech music, it means that two or more people are talking in this special way at the same time, and it can be really hard to focus on what any of them are saying. It's kind of like trying to listen to two songs playing at the same time - it's jumbled and confusing!