This is the 5917th most frequent Korean word.
사람들이다
"사람들이다" means "are people" or "they are people."
In this sentence, '사람들이다' is used to identify a specific group of people, emphasizing their presence at the referenced location.
이곳에 있는 사람들이다.
These are the people who are here.
Here, '사람들이다' describes the nature of a group, affirming them as people with a specific trait—kindness.
그들은 정말 친절한 사람들이다.
They are very kind people.
In this case, '사람들이다' serves to classify the subject as a group with a shared activity or identity—working together.