It might seem English rather discourages the use of double negations, so that the following sentences, if at all parseable, are likely to be taken as a sign of lack of education:
I haven't got no money.
I never don't do that.
The reason these sentences feel smelly is that they contain double negations which technically cancel each other, so that the sentences above might read:
I'm not in the state of lack of money
It never happens that I don't do that (e.g. never happens that I forget to do that)
But because of low likelihood of the original constructs, one would rather assume the message contain a mistake.
The second example contrasts with the situation we got in French and Russian, where we use what might seem like double negatives:
Я (I) никогда (NEVER) не (NOT) делаю (do) этого (that)
Я (I) никогда (NEVER) не (NOT) курю (smoke).
Je (I) ne fais (not do) jamais (NEVER) ca (that)
Those aren't really double negatives, it's rather that the scopes of verbs and negations are propagated differently, and actually omitting the "никогда" or "jamais" would lead to a contradiction in the message. For instance, the sentence
Я (I) никогда (NEVER) курю (smoke)
might be interpreted as comprised of claims:
- I do smoke ("я курю").
- The modality of this event, i.e. the answer to the question "how often that happens?" is: "never" ("никогда").
The two are in conflict with each other and while one could try and use this construct to deliver the idea of him not smoking, its likelihood is neglectible.
Now it seems that in Francais (though I don't really understand French yet) the situation is the same as we say:
Jamais (NEVER) plus (more) Je ne (NOT) Te dirai (will say)
while the sentence without "ne":
Jamais plus je te dirai
does sound contradictive, just as it would in Russian.
To emphasize the difference with English, let's note that we'd rather encode the message "Je ne fais jamais ca" as
I don't ever do that
Which can be decomposed to
I don't do that
My behaviour is consistent, i.e. I always ("ever") choose the policy "not do that"
My friend has given me a hint this might be coming from Latin in which both Russian and Francais have roots.
Double negatives in English
It wouldn't be true, however, to say that two negating terms cannot occur in one sentence. First and trivial, there are "Niggish" constructions like
"I ain't got no money",
which sound rather natural.
However, the case that got me curious is the use of "either" which I consider a "negating term". So, a perfectly valid example of two negating terms going in a row in English can be seen in:
-- I'm not a linguist.
-- Me neither!
Moreover, one can notice that it takes an effort to put a non-negative term in place of "either" and the following sequence
-- I'm not a linguist.
-- Me too.