Eli5: What determines if a nationality ends with -ese (chinese, japanese…), -an (Ghanian, Egyptian, American) or just the county itself (Thai)?

Question

Eli5: What determines if a nationality ends with -ese (chinese, japanese…), -an (Ghanian, Egyptian, American) or just the county itself (Thai)?

In: 4879

Answer 1

Short answer: The rules aren’t consistent, its decided based on if it sounds clunky or not.