What does the 'as' mean?
Cò = Where/Which/Who
A = From
Tha = Are/Is/Am
Thu/Sibh = You
Btw, what is the difference between Thu and Sibh?
Thu is singular and sibh is plural. So in this case asking the question directly to a single person, thu is used.
But as FionaSparr1 says "What does the 'as' mean" here?
What's the difference between Cò às a tha thu and Càite a bheil thu?