Maybe the best thing is to provide some examples.
If the original script goes:
Jackie: "You not beat me need 100 yrs more traning"
Bruce: "You're skill is not so good as you say."
Jean-Claude: "maybe you should fight someone at the same level?"
Jet: "Go Bruce. i am your supporter"
Arnie: "Ill be back."
This should become something like:
Jackie: "You need another hundred years of training before you can beat me."
Bruce: "You're not as good as you think you are."
Jean-Claude: "How about picking on someone your own size?"
Jet: "Go Bruce! I'm on your side!"
Arnie: "I'll be back."
As you can see, the editor has to not only correct punctuation and spelling, but also reword the sentences where necessary to make it sound better in English, while also preserving the original meaning.
It is very important that the editor understands when to change and when not to change. The above examples are quite extreme (but I have seen worse) and need heavy editing but most scripts aren't anywhere near that bad and only need a light touch - that depends on the TL and TLC.
Having said that, we have three editors at the moment, it's one position which is oversubscribed - but that doesn't mean people shouldn't apply anyway, positions become vacant all the time.
