This would allow you to either generate a username and see its availability (as current) or to submit a username and see its availability, possibly along with variations on it.

This generator simply alternates vowels and consonants, however, a lot of words and username use double consonants and double vowels, a good example is the word "Though", 2 consonants + 2 vowels + 2 consonants. Another good example is your username (and mine).

Could you make a list of english sound modifying patterns like SH or AU or RT and do a negative check while generating?

But it said that they both were available.

Twitter and Github always show question marks