"Ciamar a tha thu, a Mhàiri?"
Translation:How are you, Mairi?
In the vocative form used when addressing a person directly, the addition of the "a" before names/titles beginning with certain consonants causes lenition, where an h is added to the word and changes its pronunciation a bit.
cariad -> a charaid màthair -> a mhàthair piuthar -> a phiuthair Seumas -> a Sheumas
And so forth.