No shame there, I'm sure you speak English far better than I do whichever language is native to you. Now, if you decided to publish a phrase book based on your current knowledge, then we'd be having a bit of a laugh.

It’s a common error among English learners, particularly when it comes to nationalities. We would say “I am French” or “I am a French person”, but never “I am a French”.

Made even more confusing that you can do it with some nationalities but not others. So "a French" is out, but most nationalities ending "-an" are OK: an American, a German, an Afghan, a Norwegian, a Russian, an Italian. Also "-ese", though with something of an archaic air: a Chinese, a Maltese, a Portugese. Also a Swiss, an Argentine, an Israeli, because why not?

And of course pretty much any adjective can be used as a plural noun with the definite article: the French, the Dutch, the beautiful and the damned, the quick and the dead, etc.

What's more, some nationalities have specific nouns for them, but not all. A Spanish person is a Spaniard, a Finnish person is a Finn, but a German person isn't a Germ.

Then there are those that fell out of use. There are Englishmen, Irishmen, Frenchmen, but never Chinamen!