Jesus christ, how is this still going? 
 
He says Ma'am. It sounds like 'Marm' with his accent... or how some would say 'Mom'. He's not calling her his mother, regardless of the Halsey/Spartan relationship everyone keeps harping on about. Yeah, she's a prominent female figure to the Spartans, but that's pointless here. It's Ma'am. That's what he says. 

This is him,  the voice actor behind Jorge:  
http://www.youtube.com/watch?v=4oNaSoEd8Sw&feature=related 
That's how southern-English people pronounce ma'am.

Jorge is a Spartan II, the ONI lady is Dr. Halsey, the creator of the Spartan II's. He is calling her "mum", not ma'am.

" Jorge is a Spartan II, the ONI lady is Dr. Halsey, the creator of the Spartan II's. He is calling her "mum", not ma'am. "

It's literally spelled, "Ma'am" in the subtitles. Not "mom."

He's saying Ma'am with an English accent. Daniel Craig says it the same way to M in Casino Royale.

" @TheBeast said:

" He says "Ma'am", it just sounds like "Mom". "

This. It's a non-american way of pronouncing "Ma'am". "

" @The_Dude said:

" @SpacePenguin said:

" @jessej07: No its ma'am, thats what it says in the subtitles. "

Yeah but I'm pretty sure in the books some Spartans straight up refer to her as Mom, and believe it or not...sometimes subs are different from what is actually said. "

I would like to know which book you are referring too. Having read the books multiple times I'm don't remember any of the spartans ever referring to her as "mom". "

Not English . Maybe south African ? 

It actually doesn't seem to make sense that any of the Spartans-IIs would have different accents.
 
If they're picked up at six years of age, and then raised by the same people all their life, wouldn't they eventually adjust to having the same accent?
 
I know of British people moving to America at a young age having been born in the UK who now have an indiscernible American accent, and vice versa.
 

 The mix found in the speech of the settlers of a new place establishes the kind of accent that their children will develop. But the first generation born in the new place will not keep the diversity of their parents' generation -- they will speak with similar accents to the others of their age group. And if the population grows slowly enough, the children will be able to absorb subsequent children into their group, so that even quite large migrations of other groups (such as Irish people into Australia) will not make much difference to the accent of the new place. Most parents know this. If someone from New York (US) marries someone from Glasgow (Scotland, UK), and these two parents raise a child in Leeds (England, UK), that child will not speak like either of the parents, but will speak like the children he (I know of such a child!) is at school with.