[wildwood]

There's some research[1] that suggests that some dialects of Old English used double negation reliably, but that this got phased out in 'proper' Middle English.

It's interesting that double negation is standard in French, but not used in Germanic languages. In this case, it seems like the Germanic influences on English won.

[1] http://articles.chicagotribune.com/2006-11-08/features/06110...

[notahacker]

In this case, those attempting to standardize English grammar decided double negation should be used to achieve subtle shades of positive (as in Italian) rather than negative emphasis (as in Catalan) so double negatives are not conveying nothing (unlike in French or Castilian where the standard extra negative no comunica nada). Perhaps the divergence between the Romance languages is more immediately surprising...

What's interesting is that normal use of negation seems to have changed over time within many individual languages, repeatedly http://en.wikipedia.org/wiki/Jespersen%27s_cycle which is perhaps part of the reason why the AAVE double negative has so many parallels in British regional dialects and the writings of Chaucer

[hrktb]

Double negatives are recommended in proper french, but using only the first negation is actually grammatically correct(ex: je ne sais pas -> je ne sais) and keeping the second negation only is usual in casual speak (Je ne sais pas -> Je sais pas).

I always thought double negatives were a waste of time and ink, but come to think of it this kind of redundancy seems optimized for quick parsing. There is more effort on the speaker for building coherent sentences, but it's easier to catch the speaker's intent even if some parts got lost or couldn't be understood.

[unhammer]

I thinks person marking on verbs and use of articles is waste, who needs? Also, "have seen" is redundant because of "have", "have see" is better. Also, "is" redundant, many language does without. Without better.

Language is full of redundancy. Because it's a constantly evolving, very complex system of rules, it never reaches a state in which every grammatical sentence has an optimal balance between economy and expressiveness.