Dialogue isn't actually written the way people talk. It's pretty much always smoother and cleverer

A lot of it is literally just Japanese having different grammar and English translations historically being bad, and sometimes trying to account for the former by contorting the translated sentence as far as possible in English so that it begins or ends with the same word (etc.) as in Japanese because of the formatting of the text in the case of manga.

Also being overly-literal with how something is formulated in Japanese when the speaker is just speaking in a normal idiomatic way and so it would generally be better to make it idiomatic English, though that of course relates to bad translation in general.

Also also some things are just hard to translate in a way that sounds like actual English, stereotypical examples including honorifics and personal pronouns.

English translations of anime/manga don't sound like everyday language because the original text doesn't sound like everyday language either. No one on Earth actually talks like a Jojo's character

I talk like this and so do most people I know. Do you people never pause in speech?

I wonder if it has to do with Japanese acting being inspired by kabuki theater, and it would be like English dialogue all being in iambic pentameter, because English writers still keeping the format of Shakespeare?

do Japanese people actually talk like that

The answer to this actually ties into why the Japanese have such a reputation for toxic work culture. You might have heard about long hours at Japanese workplaces. The real reason for this is communication. For example, if the boss means to say ‘Hey Shinji, please write this report for me by 3:30 pm on Tuesday’, it will usually go

‘Hey Shinji…’

‘Yes?’

‘Could you…unless…’

‘Uhhh what?’

‘Write this report?’

‘Ok’

blush ‘by 3:30?’

‘Wtf there’s barely enough time wtf’

‘Oh, is that a problem?’

whips out gun and points at own head ‘I can’t!!’

‘Oh…could it be done by tuesday?’

collapses

5 hours from now, the employee has recovered from the unnecessary dialogue and is working on the assignment till 11:00 pm

It's how they think English speakers talk so they're just doing good translation.