I don't know about that, this kind of mistakes (then/than, effect/affect) are getting on my nerves as well, and I'm definitely not a native english speaker. No

I don't know about that, this kind of mistakes (then/than, effect/affect) are getting on my nerves as well, and I'm definitely not a native english speaker. Not to mention that this specific kind of mistakes (similar sounds) are at least as often from native speakers as from non-native in my experience/native language. In French, a lot of people mistake Ça for Sa for example, native and non-native alike