My first language was Welsh. I learned it from the TV when I got back from pre school. I used to get put in front of the TV, around noon, and at that time the only programmes on were Welsh language.
When we visited my Great Grandmother, Blodwyn, I used to speak to her in Welsh, her native tongue and we'd have little chats which no one else understood.
Edit: Removed an extra Great, don't know where that come from.