Post how many languages in which you can count to ten, including your native language. If you like, provide which languages. I'm going to make a guess; after you've replied, come back and open the spoiler. If I'm right: upvote; if I'm wrong: downvote!
My guess, and my answer...
Bonus question: do you ever do your counting in a non-native language, just to make it more interesting?
Actually, it's the words that the the same as native words which are the hardest to remember, IME, because you're always questioning it, or you go reaching for a "foreign" word, but if it's also a native word...
Funny little story. When I first came back from living in Germany, I'd occasionally forget the English word for things and could only remember the German ones. I don't know if that happens to many people, but that last year, I don't think I spoke English with anyone more than a couple of times.