yeah..baal is used more often in Terai ..in fact, around eastern terai..the use of baal in ktm has been very recent..all my friends in terai use baal..but many of them from Ktm haven't known of that word..eastern terai youth have a different dialect,,"billa bhayo yaar...baal diyena..bhitti ..".and stuffs like that..i have found many nepalese not aware or not using these words..