What is the source of Stiamo? I don't think we have covered this yet, have we?

It's a form of stare. Stare per means to be about to.

I was wondering how duolinguo could introduce new material like this - perhaps by first including in a dictation style question? I think I have heard the word before and could probably transcribe it "by ear" but I could not come up with the italian word as a translation from the english.