I noted two things about the language the characters used:
- Lincoln using profanity. Not much, but any at all seemed out of character.
- Black soldiers who were willing to risk seeming impertinent to the POTUS, on the one hand, and who were well-spoken and without southern accent on the other. That struck me as out of character given the backgrounds of the people in question.
In reality, even as late as the 1960s, blacks had enough difference in their backgrounds from whites as to make them seem unintelligent. Affirmative actions rationale was to transcend that apparent discrepancy. But now, of course, it is simply a racket in which peoples rice bowls are entailed. When a black can be elected POTUS, exactly where is the glass ceiling supposed to be??
Lincoln might have sworn, but obviously he wouldn't have been effing and blinding when giving speeches or interacting with the public. As for the black soldiers, they weren't all illiterate former slaves, some where educated free blacks from the North. I doubt most black soldiers would have been well-educated, but no doubt some of them were.