Learn Polish: Krawiec uszyje mi go za miesiąc. - The tailor will sew it for me in a month.

When you have a cluster of short pronouns (clitics), Polish follows a specific order: Dative (to/for whom) comes before Accusative (who/what). Here, the dative mi (for me) naturally comes before the accusative go (it).

Could I put the pronouns at the end of the sentence, like Krawiec uszyje za miesiąc mi go?

No, you should avoid putting short pronouns like mi and go at the very end of a sentence. Because they are weak, unstressed words, they need to lean on a stronger word, which is usually the verb. Placing them right after the verb (uszyje mi go) is the most natural position.

Why does za mean "in" here instead of "behind"?

When talking about future time, the preposition za followed by a unit of time in the accusative case translates to "in" a certain amount of time. Therefore, za miesiąc means "in a month". If it were describing a physical location like "behind the month", it would require a different case (the instrumental case).

The English translation says "will sew". Why isn't there a future tense helper word like będzie?