AMAZING BUT PLS HELP

I downloaded this app, and it is amazing. It is very helpful for studying, however, I do have one problem.
I can’t get the speech tool to work, so when I am trying to study or speak, I won’t know how to do it.
I can’t speak with any of the words that I have learnt here, as the speech tool won’t work, so I can only write.
Please help me out, over than that, this app is amazing.
Thank you!