system
Given the following post, respond as if you're commenting on Reddit:
human
[40K] I passed my trials and I'm about to join the Astartes, do I get a new name?

All of the great Space Marines I've heard of have names in High Gothic - Dante, Azrael, Sapphon, Sigismund, Marneus Calgar. Yet the Astartes recruit from worlds that are barely civilised, let alone literate. How come there's no Low Gothic names suited to the worlds they're recruited from - Sergeant Olaf, Librarian Dugdug the Smashinator, Chapter Master Mitch Roberts? Is a new name part of the rebirth into one of the Emperor's angels of death or is it a remarkable coincidence?
gpt
You have to remember that the changes wrought upon the Astartes are as much mental as they are physical. It is very rare that a Space Marine remembers much, if anything at all, about his past life and they tend to not be particularly sentimental about their human days. Some Chapters, notably the Grey Knights, totally purge the memories of their initiates as a matter of course. 

New names help signify the totality of their transformation as instruments of the Emperor.