I've noticed many native speakers omit the verb To Be in some sentences such as ''where you from?'', ''what you on about?'', ''what you doing?'', etc. Is it standard or just a regional thing? I know speakers of African American English often omit their ''be's'', but I've seen people of all races and backgrounds do it too.
This is atrocious English
But you're correct, it has become common in colloquial speech, especially among some subcultures. The tendency to drop the verb "to be" and its counterpart behavior, the tendency to never conjugate the verb, stem from U.S. subcultrues in the 1970s, which were derived from the "Jive" lingo from the African-American jazz culture of the 1930s and 1940s. Both behaviors are ungrammatical (unless the world today has decided to become accommodating, language is fluid).
An example of dropping the verb comes from the 70s popular TV situation comedy, "Diff'rent Strokes."
What you talkin' 'bout Willis?
An example of not conjugating the verb comes from a more recent experience. While helping a friend prepare to test for his commercial driving license, he would chant through the pre-drive test and check procedures like this:
We be looking at the tire guage depth...