"Bah" is a colloquial term used in Sabah - similar to the Malaysian-Singaporean word "Lah". However, bah is not lah and has its own distinct connotation. This video briefly outlines the multiple ways to use Bah in everyday context.
[edit* Thank you for all your comments. Today I learnt that Bah is used throughout all of Borneo! This makes me even more proud! ]
If you're Borneon, tweet #canBAHifyou and let me know other ways you use Bah!