Sharlto Copley's accent in Elysium?

It is supposed to be a an Afrikaans accent from lower class people in the Johannesburg area. There are also some English South Africans who sound like that, even though they aren't Afrikaans speaking. Many Coloured people in South Africa also sound like that when they speak English. The accent is somewhat over-the-top, but there really are people who speak like that.

Most Afrikaans people do not speak like that, or at least do not have an accent nearly as thick. Stereotypically, Afrikaans people who were too stubborn to learn English properly, ended up with an accent more or less like that. In other words, it is used in movies and commercials when the person is not supposed to be too bright and too stubborn to learn. But because it is so unique, many people seem to think that this is the one and only South African accent. In truth it represents a small minority of South Africans. There is no such thing as one South African accent.

In South Africa we have 11 official languages. Afrikaans (and even English) have slight regional dialects. So, depending on your mother tongue, the dialect you speak it in, the dialect of English you learn and how good you are at languages, you will end up with a specific dialect/accent.

The actor Sharlto Copley is English and speaks English with a Johannesburg dialect. You can find many interviews of him on youtube and listen to his natural dialect. Also, you can hear that many Afrikaans people from Johannesburg sound similar (even though they are Afrikaans) - Oscar Pistorius etc. You could also listen to the director of District 9/Elysium - Neill Blomkamp - an Afrikaans person who doesn't quite have the same accent - even though he is also from Johannesburg.

Yes, it is very difficult to pull of. Even for some South Africans. Most people usually go with a German/Russian accent with some Australian thrown in. But instead of overdoing it, they should actually try to tone it down, then it sounds more realistic.