I'll just add a little to what people have said...
GoldCoinLover said:
1) Is the U NEVER pronouced? For example, if you had a word such as:
IRRHASSIMASU. I know that if the U is at the end, you usally don't pronouce it. However, what if the U is in the middle of a word?
Both /u/ and /i/ are normally voiceless (which makes them sound whispered) when occurring between two voiceless consonants (p, t, k, s, sh). For example: <takusan - 沢山> (many), where the /u/ is voiceless because it is between /k/ and /s/.
This also happens to /u/ and /i/ at the end of an utterance when they follow a voiceless consonant (p, t, k, s, sh); commonly with the ending <-masu> that you mention. /u/ is generally dropped in these circumstances, unless someone is trying to pronounce a word with deliberate care. I'm not entirely sure if /i/ is also commonly dropped in these circumstances....I can't remember noticing, and also can't think offhand of an example word (I'm sure there's a really obvious one that I'm missing
). You would be quite safe not pronouncing /u/ in those circumstances. Only after voiceless consonants though....it is pronounced in full otherwise.
3) Is it possible to spell something in japanese (like a whole sentence) using only kana? Would this make sense? More importantly, if I wrote something this way in kana only, could another japanese person in tokyo who does not know english understand it?
If it is short, then it would likely be understood. Reading longer sentences that are only in kana is sometimes quite a challenge though; kanji break up the sentence visually, and make it quicker to read. It can help distinguish between different words with the same pronounciation, and so the same kana....you can often know what is meant by context though.
If you aren't leaving until a year, you would have no problem learning some basic Kanji. There are a few that turn up all the time. I would mention some, but I have to go now. I'm sure someone can fill you in or give you a link if you want to know which Kanji are most common.
Psszt, how do you say welcome...ANATA NO YOKODAIKUMASU?
You can say ようこそ(yテエkoso)