yeap like ster2006 said it really depends on how hard you try and ur background
i go to church and we have lots of Japanese people so i hear japanese a lot also i have some relatives who 's japanese
I love watching japanese animes / dramas / games and took Japanese during my highschool years (that's 3 yrs)
so i can read and write hiragana and katakana ( some kanjis i've learned in korea) and know whats going on when i hear japanese
Jap grammar is very similar to korean so its lot easier for me than an american trying to learn them
good luck to you if u descide to learn jap