I've said this once before, might as well say it again.
I you mean just talking in japanese phrases, then you can learn it quick
If you mean learning how to talk, particles, hiragana, kanji, katakana, basically knowing how to read, write and speak, then you're sadly mistaken.....it takes a while to learn it...cant really learn it quick.
I myself have learnt japanese till age of 6. Most of it ive forgotten and all I can remember in terms of writing the characters is 1st grade kanji...
Basically what Im trying to say is that to fully understand japanese, it'll take about a year or so.
as the old nihongo saying goes:
JAPANESE LANGUAGE SHOWS OUT THE DETERMINATION AND STRENGTH OF OUR COUNTRY
so....you have to be determined to learn it