Warning: Grammatical Change
Many think grammar is a set of fixed rules. Actually, it's whatever people think is acceptable. Proper grammar is what people who grade English papers think is acceptable.
In Leiter Reports, a potential law student writes: "I am a top candidate....my GPA [is] 3.82, and [I] scored 178 on the LSAT. I have been accepted at NYU, Stanford, and Harvard; did not apply to Columbia; and am still waiting on a decision from Yale."
Wow. A generation or so ago, anyone (much less at "top candidate") who used "waiting on" instead of "waiting for" would sound like a hick. I still can't bring myself to say "waiting on" unless I'm referring to a waiter.
I suppose we'll know this phrase has completely turned the corner when the latest edition of Beckett's En Attendant Godot is translated Waitin' On Godot.