Thanx all for ur comments.......I used to talk same word  when I was in nepal.I didnot realise that this word is being popular day by day.......as I entered USA .....I heard same word on the very first day.....some nepali guys were chating using the same words even in Airport......so I thing the most sopken word in nepali among youth is non other then Baal.........i was jus curious to know what actually is....?