its ok for basic spelling mistakes but has real difficulty with some words people would spell phonetically I'm dyslexic so I spelled definite like this defenate. The add on offered me two options to correct the mistake defecate and def enate. I'll forgive defecate as the app could have thought it was a mistype but to not offer definite when I typed it in google and the correct spelling was the first thing google offered. Also loads of names of places are flagged as a mistake Shinjuku for example. I wouldn't recommend this add on in its current state.