I've never thought about this before, and it is strange. From the Wiki article on demonyms though, "Often, demonyms are the same as the adjectival form of the

I've never thought about this before, and it is strange. From the Wiki article on demonyms though, "Often, demonyms are the same as the adjectival form of the place, e.g. Egyptian, Japanese, or Greek." I guess you'd also not say "I am a Japanese", but probably just "I am Japanese"?