This is the 509th most frequent French word.
tu
"You" (informal, singular).
In this sentence, 'tu' is used as the subject pronoun addressing a single person informally. It is the second person singular form in French.
Tu es très gentil.
You are very kind.
Here, 'tu' is inverted with the verb 'vas' to form a question structure, maintaining its role as the subject pronoun for informal and singular address.
Où vas-tu?
Where are you going?
This example demonstrates 'tu' in a declarative sentence, continuing its function of denoting the informal second person singular address.