This subproblem is called "bigram detection", or more generally "n-gram detection" for phrases of > 2 words. I'm not going to give away Google's algorithms, bu

This subproblem is called "bigram detection", or more generally "n-gram detection" for phrases of > 2 words. I'm not going to give away Google's algorithms, but you should be able to look up public academic research with that keyword.