In the sub game "word blend" it starts by saying a word which you then have to write down.
This becomes harder in the next level as 2 words are spoken at the same time.
Place your thumb over one of the speakers and you will only hear on of the words, move your thumb over the other speaker and press "try again" and you will hear the other word.

This makes it a bit easier in the next level when 3 words are spoken as well.