it just grates on my nerves!
I hear ya! Despite my linguistics background and experience living in various countries and having contact with different cultures, etc., I still feel irked, riled up, or what have you when I hear certain constructions. That is, of course, human nature, though it still is no excuse!
Still, that is probably the way that their parents spoke, and so it's only natural for their speech to have the imperfections of those with whom they grew up, but most people to whom I've talked have said that they do this because it saves time instead of considering the conjugations! I would have thought that this would have come instantly.
I must admit I'm not comfortable with your use of the word "imperfections". That presupposes comparison to a superior form of the language, which I had hoped we agreed is a social, rather than salient, concept.
One other thing, it's always important to keep in mind that the reasons people give for doing something aren't necessarily the actual reasons, whether they themselves believe them or not! "Saves time" might be a convenient explanation, but it still seems more likely that the real reason is "that's the way I speak this language most naturally". Would you force yourself to speak in an unnatural-to-you manner if it seemed there was no problem with communication?
As for Japanese, I can understand (and speak with varying degrees of proficiency) several dialects, including 2 varieties of Kansai (Osaka-Kyoto) dialect, Shizuoka-Yaizu dialect, 3 varieties of Nagasaki dialect (Nagasaki, Isahaya, and Goto Island), Kyushu dialect as spoken in Fukuoka, and of course the "standard" Tokyo dialect. These are all quite different from each other, including grammatical endings, intonation patterns, and so on.
And as far as I know, my brother doesn't speak Spanish, though I wouldn't be surprised if he could decode the majority of your message.
