Aha - the skeleton in the closet...
No, my mother was English - from East Anglia - and spoke no Welsh until she learnt when I was 7 or 8. My father was brought up in Port Talbot and London. His mother (my Nana) spoke perfect Ceredigion Welsh (she was from Glynarthen, a few miles from Tresaith, but her father was from a Morriston / Landore family). Unfortunately, his father was from Newport, Gwent, and his only Welsh was "Mae'r iaith Gymraeg yn anodd iawn", sung to a tune that ended "Tarara boom di ay".So while my dad speaks Welsh, he's never been particularly confident in it. Happy to preach in Welsh (in chapel, that is), but not really have very wide ranging conversations.
So, my Welsh is a combination of Nana's Ceredigion / Swansea Welsh, a big dose of the beautiful Welsh spoken by the old people of Rhymney when I used to spend time there with my father, as well as all the activities and Welsh speaking friends that my far-sighted parents steered me towards.
Bet you're glad you asked now!