A few years ago I wrote a post with tips on using various accents (diacritical marks) on the English QWERTY keyboard without switching languages, which can be a distraction if not real pain.
One mark that I missed was accent grave, i.e. the accent in French that goes upwards and to the right.
To type it, press the Option (alt) key and type accent grave key, the one to the left of Z on the QWERTY layout. You will see the (sometimes) yellowed accent grave. Type the letter you want with this accent — and it's done.
In French, the presence or absence of this accent can make a huge difference. When you mean 'where to' it's à; when you mean 'have' or 'had' it's a without the accent. When you mean 'or' as in either or, it's ou, but when you mean 'where' [is it], it's où.
Mind your French, folks!
Other accents still work the same as described in my old post.