Possibly, depending on regional dialect. Also acceptable is "what y'all're" or "what-y'all're". Edit" also "t'y'all're". Note that many of these sound much be

Possibly, depending on regional dialect. Also acceptable is "what y'all're" or "what-y'all're". Edit" also "t'y'all're". Note that many of these sound much better said then they look written.