It's almost like, "use or lose it". My brothers, sister, and I grew up speaking Turkish, however we only spoke it to our mother. Our mother was a single parent, for most of our lives. We didn't have one other family member, in the U.S. who spoke Turkish. As we got older and became adults, thus beginning our own lives, we didn't have that daily verbal interaction with our mother, as we did when we were children. It became very apparent, who spoke the least to our mother. Actually, my younger brother never spoke Turkish very well, so when he was a teenager, he often spoke English to her.