This new male speaker has a speech impediment. He butchers many French words: his vowels are sloppy and inconsistent and he adds extra -uhs after the ends of some words. Don't feel bad you can't always understand him and certainly don't imitate him. The female speaker has a standard French accent - imitate her
I don't think it's a speech impediment, it's just that he pronounces French in the style that is common in the south of France. Or so I've been assured by many native speakers. It's probably not a bad thing to be exposed to more than one dialect even if it makes it harder at first.
Good/interesting question. See the discussion here: http://forum.wordreference.com/showthread.php?t=1509815 As for the grammatical guideline, it seems to me that grand-somethings (grand-place, grand-messe, grand-chose, grand-voile, grand-croix) always use the masculine "grand" form, regardless of the grammatical gender of the following word. This includes the plural forms (grands-mères, etc.)
Not sure as I am a native (and we usually don't "learn" that kind of "rules"), but I'd say that it's because they're fixed expressions and, most of all, the word "grand" here has not its proper, original meaning (my "grand-mère" can be shorter than I, for instance). This can be found in other compound nouns with the adjective "grand" that does not take the feminine:
la Grand-Place (de Bruxelles, my hometown) = the main square in the city. In Spanish, it is "la Plaza Mayor": you can see that "grand" here is not about the size but about the fact that it is the "central, major" square of the city. But maybe other squares are bigger.
la grand-route = the main road.
grand-chose: very commonly used, e.g. "Il n'y a pas grand-chose à faire" = "There is not much to do" / "C'est pas grand-chose" = "It's no big deal".
It's the same with demi-[relative] - both grand-[person/thing] & demi-[person/thing] are being treated as a single unit, so only the ending of the whole unit changes. Different from "grandson, etc." where petit is treated as an adjective attached to the person being described, and changes with the person: "Petit-fils, petite-fille, petit-enfant, petits-enfants*. I don't know why, but that's just the way it is.
I don't see anything wrong with "mild":