[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.