If you can learn a language in a week, I'll eat a whole broomstick

Do you know what makes me mad? It's the current trend for "Learn a language in a week" CDs to be given out with your Sunday newspaper. So presumably you idly peruse the sports pages in the morning, then slip your CD into the machine and by, ooh, teatime you'll have mastered the present tense and all the subject pronouns. And by Wednesday you'll be forming complex sentences and starting on the subjunctive.
It's madness. If you were to study for 24 hours a day for the entire week you'd probably be able to ask for a beer and a room by the end of it, but what about all that vocabulary it takes a lifetime to learn? Even if you're a native English speaker I bet you don't know what honorificabilitudinitatibus means, do you? (Neither did I - I had to look it up). And what about all those idioms? In English we might talk about someone being "a chip off the old block", or we might comment: "It's an ill wind", or "What goes around comes around....".
Foreigners would be totaly flummoxed by these idioms (flummoxed? Is that a word?) And of course, they have their own quirky idioms. For example: the "I'll eat a whole broomstick" reference in the heading is the German equivalent to "I'll eat my hat" in English. Why? For the same reason, presumably, why it "rains cats and dogs" in this country whereas in Sweden it "rains small nails" and in France it "rains like a urinating cow".
People who think they can learn a language by investing only one week of their lives are the type who want their cake and eat it. Or who want their butter and the money for the butter, as the French would say. Or as the Italians put it, who want their full bottle and their drunken wife.