You're doing copyediting, period. If you're addressing massive systemic problems in the work you are copyediting it.
(To be honest, if you're only having to fix the occasional thing here and there, you're still copyediting, just not hugely so.)
On the subject of dialogue, you need to make the distinction between errors on the part of the author and eye dialect -- the latter is the deliberate use of misspellings to establish a character with poor education, a strong accent, and so on. Eye dialect is a common tool of writers and is perfectly fine. I've used it in Drunkard's Walk -- Doug, for all that he's an Ivy League-educated genius, dips into eye dialect when he's being especially informal -- and in things I've written for My Apartment Manager Is Not an Isekai Character like Ranma Saotome's voice. If the author, however, is prone to systemic errors in grammar and usage, you'll need to figure out whether or not the character is supposed to talk that way, or if the writer's errors are changing how he should be perceived.
(To be honest, if you're only having to fix the occasional thing here and there, you're still copyediting, just not hugely so.)
On the subject of dialogue, you need to make the distinction between errors on the part of the author and eye dialect -- the latter is the deliberate use of misspellings to establish a character with poor education, a strong accent, and so on. Eye dialect is a common tool of writers and is perfectly fine. I've used it in Drunkard's Walk -- Doug, for all that he's an Ivy League-educated genius, dips into eye dialect when he's being especially informal -- and in things I've written for My Apartment Manager Is Not an Isekai Character like Ranma Saotome's voice. If the author, however, is prone to systemic errors in grammar and usage, you'll need to figure out whether or not the character is supposed to talk that way, or if the writer's errors are changing how he should be perceived.
-- Bob
I have been Roland, Beowulf, Achilles, Gilgamesh, Clark Kent, Mary Sue, DJ Croft, Skysaber. I have been
called a hundred names and will be called a thousand more before the sun grows dim and cold....
I have been Roland, Beowulf, Achilles, Gilgamesh, Clark Kent, Mary Sue, DJ Croft, Skysaber. I have been
called a hundred names and will be called a thousand more before the sun grows dim and cold....