Questions & Answers about Пожалуйста, дай мне кусок хлеба.
Дай is the imperative singular form of the verb дать (to give). It means give!
- дать = the dictionary form, to give
- дай = give! when speaking to one person
- дайте = give! when speaking to more than one person or when being more polite/formal
So Пожалуйста, дай мне кусок хлеба means Please, give me a piece of bread when addressing one person informally.
Because Russian changes pronouns depending on their role in the sentence.
Here, мне means to me and is the dative case form of я (I).
Compare:
- я = I
- меня = me
- мне = to me
- мной / мною = by me / with me
Since the idea is give to me, Russian uses the dative:
- дай мне = give me / more literally, give to me