"American" is either an adjective or a singular noun. "Japanese" is either an adjective or a plural noun. "People" is mostly used as a plural noun, but it can be used as a singular noun too (see below). Sorry, English is pretty messy sometimes. 1. American people are good at making compliments. ("people" is plural) 2. Americans are... ("Americans" is plural 3. An American is... (you need to use An or The) ("American" is singular) 4. Japanese people are... ("people" is plural) 5. A Japanese person is... (you need to use A or The) ("person" is singular) 5a. Japanese people are... ("people" is plural) You can also use "The American people" and "The Japanese people" of "The Japanese" to refer to the all the people of a country or of an ethnic group. It is technically a singular noun, but it still uses the plural (are, have). The American people have a diverse history. The Japanese people have a rich history. The Japanese have a rich history.

1 person is and many people are for singular we use is and plural we use are

1. Are 2. Are 3. Are 4. Are 5. Both Are and Is depending on what you want to say next. But is here would make more sense These still confuse me sometimes xD but pretty much how I understood the different. "Are" is usually used after a plural, so "American people are..." that is more than one. If you want to say is in that sentence you could say, An American person is... Number 5 I said both because I don't think there is a plural for the word Japanese. So you can choose either Are or Is depending on the context. I can give you an example. Are: Japanese are friendly Is" Japanese is a hard language. Another word like this would be "sheep" : ) it can be singular or plural depending on how you word the sentence. I hope I haven't confused you : (