That only doubles the size of the attacker's dictionary, though. Instead, I'd say "pick random words and add a few random typos". As long as there aren't too

That only doubles the size of the attacker's dictionary, though. Instead, I'd say "pick random words and add a few random typos". As long as there aren't too many the typos will be as memorable as the words themselves (more so if you're a spelling pedant like me), and using a variety of typos instead of just one simple transformation increases the search space a lot more.