There was a poll about this recently that I found interesting.
There are different ways of doing it: summarising what the PC is saying, having the player choose every line they say, or having the player choose a general theme of what they say and writing out the dialogue. The poll pretty strongly went for the latter option.
I like my PC’s dialogue not to be too long before a choice, because if there is a large amount of text without my input, it’s more likely for my character to say something that doesn’t match what I thought I was choosing. If you want to go more complicated, you can track personality traits that shift the tone of the dialogue that you write.