Learn Russian: Дим, дай мне книгу, я хочу немного почитать. - Dim, give me the book, I want to read for a bit.

This is the colloquial truncated vocative case. When addressing someone directly in informal spoken Russian, short names ending in -а or -я often drop that final vowel. So Дима becomes Дим. It makes the address sound more natural and intimate.

Can I form this truncated vocative with any Russian name?

No, this only works with informal, short-form names and kinship terms that end in -а or -я, such as Маша becoming Маш or мама becoming мам. You cannot use it with full formal names like Дмитрий or names that end in a consonant.

Both немного and the по- prefix in почитать mean "a little bit". Isn't using both redundant?

Logically, yes! The prefix по- in почитать already limits the action's duration, meaning "to read for a short while". However, combining it with немного is perfectly natural and very common in everyday Russian. It just emphasizes that you really only want to read for a brief moment.

Why use the perfective imperative дай here instead of the imperfective давай?