[QUOTE=fetus]
We all have areas we’re a little ignorant in–for example, I just found out today that Scots is its own language, when before I just thought it was an incomprehensible dialect of English.
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Actually, as Omi no Kami says, in the field of linguistics there doesn’t really exist a distinction between “language” and “dialect”. So the question of whether Scots is a language in its own right or an incomprehensible dialect of English is mostly meaningless.
I’ve read a few – presumably non-linguistically accurate – definitions of what it means for two dialects to belong to the same language. One of them says that it requires that they share at least 80% of their vocabulary. That’s interesting, but at the same time, there’s a lot more than simply vocabulary that distinguishes languages from each other. Two dialects could have a similar vocabulary but so different accents that they are barely mutually intelligible. Another definition is just that: two languages are the same if they are mutually intelligible. But the fact is that mutual intelligibility isn’t transitive: if A and B can communicate with each other in their own language, and B and C also can, there’s no guarantee that A and C will be able to communicate with each other. So are A and B speaking the same language, and B and C speaking the same language, while A and C aren’t?
Consider the case of Hindi and Urdu, spoken in India and Pakistan, which I am given to understand are similar languages, though mutually unintelligible in their “pure” versions. Between the places where “pure” Hindi and “pure” Urdu are spoken, a whole spectrum of dialects going from one to the other is spoken. Also consider Afrikaans, which became a language when South Africa decided to make it one of its official languages instead of Dutch.
(By the way, if I’m saying something incorrect in this post, can one of the actual linguists correct me? I’m only an interested amateur.)
As for GuyNblueJeans’s (and others’) confusion, I think a lot of it stems from the fact that much effort has been done by prescriptive grammarians and teachers to stigmatize language that deviates from the prescriptive “norm” as “lazy”. Of course, being lazy is morally objectionable, so speaking lazily should also be, right? And on the surface it does seem that saying “libary” or “nucular”, for example, means replacing sounds that are “hard to say” with others that are easier, which means not having enough regard for the language to use it correctly, which means being lazy. But it’s not actually objectively true. It isn’t harder to say “nuclear” than to say “nucular”, but the second one contains sounds that are less unusual to speakers of some English dialects, which is why it is the pronounciation they use. My first language is French, and I’m sure it contains sounds that many of you wouldn’t be able to pronounce, while I have no trouble at all. But that doesn’t mean you’re lazier than I.
I think it’s been shown that as languages evolve, you can never say that they become “more complex” or “less complex”. As structures disappear (with people lamenting their disappearance), others appear.
So it isn’t lazy to speak the way you’ve been told not to speak because it’s “lazy speech”. But this doesn’t mean that people shouldn’t learn a normative dialect. For better or for worse, not a single dialect (or register) is appropriate for all situations. So the way you speak with your friends isn’t “wrong” or “lazy”, and you shouldn’t be ashamed of it, and maybe from it will evolve the normative dialect of a few centuries from now. But at the same time you can’t really use it for a job interview today if you want to impress people. That’s what being a naked ape is all about. 
