Romance languages

decrepit is the word you're looking for

By the way, read the "trivia" note in that entry. It's delightful.

I wonder what accent your mental voice speaks with when reading Portuguese: French phonology all the way, or do you try to spice it up a bit based on your knowledge of other Romance languages (and maybe of Portuguese itself, even though you don't know it)?

On a different but related note: can one's mental voice when reading foreign languages have a better accent than when one actually speaks the same language out loud? I don't think so because in the end my personal feelings is that accent has more to do with how our brains processes the sounds of language than with the vocal apparatus (even though it's also important obviously), but I may very well be wrong about this.

Come to think of it, it's similar to what happens to me with singing. When I have a song in my head, it sounds fine. But when I actually sing it, it's awful.

I'd say it's a little more than that. I know there are exceptions, but that's what they are, unless the phenomenon is more widespread than I thought.

That's a bit what I was getting at -- or coming from, to be more precise: I think having an ear for language is pretty much the same as having an ear for music. And the thing is, people who sing off-key certainly lack the physical training required to sing in tune, but they also lack the ear training. If the music in your head really sounded fine, then you should be able to take a violin and play in tune. Maybe laboriously, and you wouldn't hit the right notes on your first try, but you should be able to hit them eventually, and know you have hit them. Problem is: that just doesn't happen. At least not in the overwhelming majority of cases. It's not that (most) untrained people can't sing or play in tune: it's that they can't hear in tune. And my hypothesis is that the same is true for language. Or for painting, if you transpose the problem to the visual domain. The "big picture" might look fine in your head, but if you look closer: are you sure your perspective is right? The proportions, the anatomy, the exact hue of the shades? Being able to form a "correct" representation in your head of something is IMO the hard part of most anything. I still remember what a comic artist friend told me years ago: drawing is all about "seeing". Sure, we might not have the muscle memory required to then produce a physical version of it as deftly as an expert would, but my theory is that it's secondary: it's all mostly in the head.

Now, like I said, the muscle part is important as well. Being able to draw a smooth-looking "perfect" circle takes muscle training for instance. Realizing some phonemes the right way does as well, and even if you could nail them in isolation, getting them right in actual speech would be harder. So you're probably right in saying that it's possible for one's "mental accent" to be better than one's actual accent, but my revised view is that the discrepancy might not be that large.

I mean, I'm not claiming that I hear foreign languages in my head with 100% accuracy, but I definitely do so with more accuracy than I pronounce them. The proof is that, very often, I know that my pronunciation of this or that is off, but it just won't come out of my mouth the way I hear it in my head. And if someone tells me "you got that wrong, it should sound this way" I'm like "well, I know... but it just comes out wrong somehow". (That can be frustrating because it basically makes me sound more ignorant than I am. I know, but my mouth won't obey me.) If it were only a matter of hearing things wrongly, I wouldn't even realize my pronunciation was wrong.