Fifty hours and a final exam

Is it possible to learn to speak Chinese in a week?

I doubt it, but my son John and I are finishing up a fifty-hour experiment in Mandarin immersion -- thirty hours of instructional CDs , ten hours in the classroom, and ten hours of tutoring with a Shanghainese college student. It's spread out over ten weeks or so, but the total is just over a week.

Observations: While the grammar is simple -- the verbs don't conjugate and the nouns are the same regardless of number or gender -- the pronunciation has been a puzzlement. The use of four major tones as well as a neutral or flat tone, plus an umlauted /u/, mean that Mandarin has in effect thirty vowels -- at least, the way I see it. This straightforward exchange illustrates the challenge:

"Shì sì suì? Haíshì shì shí sì suì?" -- "Bu shì, shì sì shí sì suì, keshì shì sĭ."

Translation: "Is it four years old? Or is it fourteen years old?" -- "No, it is forty-four years old, but it is dead."

The pronunciation sounds something like "Sh-ss-sw? High sh-sh-ss-sw?" -- "Boo-sh, sh-ss-sh-ss-sw, k'sh sh-ss." Granted, this is a tongue twister even for the Chinese, but for an American, distinguishing the difference between "shì" (to be) and "shí" (ten), or between "sì" (four) and "sĭ " (dead), takes a new level of concentration. And this doesn't even begin to address the written characters - if it weren't for the romanized "pinyin" I'd be totally illiterate.

Final exam starts soon. Results will be posted afterward.