It’s strange how some nationalities end in “ish” and some end in “ese” for example English and Chinese. And looking for patterns is hard. First I thought maybe it was where they are from because in Asia we also have Japanese but then we don’t call Koreans Koreanese do we 🤔
And then there are so many other suffixes just to confuse people more.

In the search to solve this conundrum I found this interesting map.