I’ve done that type of work too, but you have to hate bad grammar and know it’s wrong before you can do the job in the first place. So I think it’s from my early education, and certainly from reading a lot.
I’m learning Russian at the moment, and for a native English speaker, it’s a real mind-bender.
For example, double or even triple negatives are not only allowed, but necessary.
If you want to negate a sentence, you have to negate every part of it. So instead of saying: “I don’t go anywhere.”, it would be: “I don’t never go nowhere.” In Russian, this is not contradictory - it’s just making all the parts of the sentence agree, so it’s logical - just not English logic. If the destination is “nowhere”, you cannot literally go there, so you have to NOT go there.
So if I start typing double negatives, you’ll know I’ve spent too much time doing Russian, so it’s starting to sound OK.