If you’re making a design for someone other than yourself or your client, use fonts that work in languages other than English. If you’re making a theme for public distribution, pick something that at least includes extended Latin, and preferably has a few other alphabets as well.
Hell, if you’re making a design just for yourself, use fonts that work in languages other than English. You can be the most monolingual American on earth, and the minute you copy/paste something that’s a little more worldly, all those accented characters will fail over to your fallback font. It looks awful. It looks unprofessional. And it looks like you haven’t considered any audience that isn’t just like you.