Learn Swedish: Chefen ber assistenten att få talet skrivet. - The boss asks the assistant to get the speech written.

They mean different things in Swedish! You use frågar when asking a question to get information. You use ber (from the verb be, meaning to request or pray) when asking someone to do an action. Since the boss is requesting a task, ber is correct.

Why is the word skrivet used instead of skrivit or skriven?

This sentence uses the resultative causative construction: få + object + past participle. In this structure, the past participle acts like an adjective describing the object. Because ett tal is an ett-word, the participle takes the neuter -t ending, becoming skrivet.

I thought talet meant 'the number'. Why is it translated as 'the speech' here?

The word ett tal has two very common meanings: a number (in math) and a speech (given to an audience). Context tells us which one it is. Since the boss wants a text written by an assistant, 'the speech' is the natural fit.

Does the phrase få talet skrivet mean the assistant will write the speech themselves?

Not necessarily. Just like the English phrase 'to get the speech written', this construction focuses on the end result rather than who exactly holds the pen. The assistant might write it, or they might assign it to someone else. The boss just wants the finished product.