'People' is plural. The words 'persons' also exists, but that tends to be used more in formal and legal contexts. Most of the time, we use 'people' as the plural of 'person'. So the grammar of the rest of the sentence has to agree with the plural subject. For example: How many people were there at the party? Not many people speak that language. A lot of people are living here. NB Very occasionally, you can use the word 'people' in the singular to mean a particular tribe, race, or ethnic group. But this is very unusual. 99.99% of the time, when we say 'people', it is a plural noun. 'People' may look singular, and the equivalent word in your own language may be singular - but if you mean one person/ two people, it is most definitely plural.

It's the plural form of "person"

plural