"All your ___ are belong to us"

<<I don't think very many people say that. As JJM explained, there is no such thing as "incorrect grammar" as spoken by native speakers, but there definitely can be in terms of nonnatives. Also, this doesn't apply just to English but any language.>>

Not applied to Spanish. Even native speakers can speak broken Spanish, I speak broken Spanish sometimes, when I get nervous.

<<"All your base all belong to us," is bad English - but not constructed by a native speaker, rather the Japanese.>>

That is not bad English, it's "ENGRISH". And "All your base are belong to us" is one of the most well known phrases imported from ENGRISH to the ENGLISH language, it's even a cheat code in the game Warcraft III, I guess. If you want to know what ENGRISH is and why do they call it that, check this:

http://en.wikipedia.org/wiki/Engrish

<<Not applied to Spanish. Even native speakers can speak broken Spanish, I speak broken Spanish sometimes, when I get nervous. >>

But that's not really "broken" as it doesn't include nonnative grammatical errors. What we mean when we say this is that from an objective linguistic viewpoint there is no such thing as "incorrect grammar" as applied to native speakers of any language (no matter what prescriptivist norms say--those at best apply to formal written norms). And yes, this definitely applies to Spanish as well.

And what do you think of this, dear Kirk:

"Oye, ehhh, yo... mi coche... puedo... si tu... llevo?"

What I meant was "Si tu deseas, te llevo en mi coche" ("If you like to, I'll give you a lift")

I said that a couple of years ago. There was a very beautiful girl, I was speechless. But I tried and offered to take her to college in my car. And, sadly, I said it in that so clumsy way that she just laughed and ignored me.

Isn't "Oye, ehhh, yo... mi coche... puedo... si tu... llevo?" broken Spanish?

If what you say, and what you have always claimed, that there is no "incorrect grammar" as applied to speakers of any language, then the sentence above is correct Spanish? Just because I, a native Spanish-speaker, said that, does that mean any bunch of words I say magically are correct Spanish?

That doesn't make sense to me.

<<"Oye, ehhh, yo... mi coche... puedo... si tu... llevo?">>

Said either by a native-speaker or a non-native speaker, it IS incorrect Spanish. There's no grammar there, there's no sense, no coherence, there's nothing but just words without a clear meaning. That, in my opinion, is broken Spanish.

<<Just because I, a native Spanish-speaker, said that, does that mean any bunch of words I say magically are correct Spanish?

That doesn't make sense to me.>>

Hehe, and rightly so ;)

When people say that native speakers of a language don't make mistakes they mean that when they speak naturally they are not using "incorrect" grammar (no matter what a formal prescriptivist guide says). Of course I theoretically could contrive something like "I on top of table apple the put" and it would be ungrammatical because no native speaker of English would say that. However, saying something like "Me and my friends went to the museum" is not a "mistake" even tho it doesn't conform with formal written norms. That's what people mean when they say native speakers don't make grammatical mistakes.

A comparable example in Spanish would be "habían dos hombres en la plaza" instead of "había dos hombres en la plaza." Yes, the former example is not considered acceptable in formal writing and is supposedly "incorrect" as considered by the Royal Academy but millions of native speakers use that form all the time, and it actually has long existed in many Spanish dialects (both Iberian and Latin American) before rather arbitrarily being considered "incorrect" by the Academy in more recent times. From an objective linguistic point of view (not a formal-writing prescriptivist one), "habían dos hombres en la plaza" is acceptable in Spanish because it is a natural form used by native speakers.

Of course, sometimes people stammer and stutter and have pauses and "uhs" and all that stuff but that's not really within the realm of what I'm talking about (that's also pretty peripheral in terms of overall language usage).

<<When people say that native speakers of a language don't make mistakes they mean that when they speak naturally they are not using "incorrect" grammar (no matter what a formal prescriptivist guide says). That's what people mean when they say native speakers don't make grammatical mistakes.>>

Yes, I agree with that.

<<A comparable example in Spanish would be "habían dos hombres en la plaza" instead of "había dos hombres en la plaza." Yes, the former example is not considered acceptable in formal writing and is supposedly "incorrect" as considered by the Royal Academy but millions of native speakers use that form all the time, and it actually has long existed in many Spanish dialects (both Iberian and Latin American) before rather arbitrarily being considered "incorrect" by the Academy in more recent times.>>

Yes, you made a very good point there. Some people find the first sentence unpleasant and incorrect. And for others it's just natural, they don't even think about it's correctness when they speak. Of course, everything changes when these two kinds of people meet each other. ho ho ho.