Learn Hardcore German: Die Leute in der Stadt sind freundlich.

Leute is a plural noun in German. Plural nouns always take the article die regardless of their grammatical gender in the singular. So we say die Leute, meaning "the people," and the verb must also agree in number (“sind” instead of “ist”).

Why is it sind and not ist?

Because Leute is plural, the verb should also be in the plural form. Sind is the plural of ist (“they are” vs. “he/she/it is”).

Is Leute the same as Menschen?

They can both mean “people,” but Leute tends to be more casual and often refers to a group of people you might see around you, while Menschen is more formal or generic. In everyday conversation, Leute is very common.

Why does in der Stadt use the article der?

The preposition in can be followed by the dative case when indicating a location. Stadt is a feminine noun (die Stadt). In the dative case, the feminine article die becomes der, so in der Stadt is the correct form.

Why doesn’t freundlich change its ending here?

When used after the verb sein in the predicate (i.e., “they are friendly”), adjectives do not decline and remain in their base form. If freundlich were used before the noun, such as in freundliche Leute, it would take an ending.