Anecdotally, from what I've seen in various languages, native speakers do seem to make more mistakes that are tied to spelling/pronunciation (than, then, their

Anecdotally, from what I've seen in various languages, native speakers do seem to make more mistakes that are tied to spelling/pronunciation (than, then, their they're in English, aller, allé in French) whereas non-native speakers make more grammar mistakes (for example I tend to put articles at wrong places or forget them in both English and French, but the spelling mistakes are absolutely jarring).