Having lived in Southern California my entire life, speaking a little Spanish was to be expected. All or most of our posted language used the two languages as double translation: English on top, Spanish below. I never really thought of myself as bi-lingual until one day I was driving with my mother when she asked me a simple question. I found myself answering in Spanish and realized I had to answer in English. Imagine my surprise when I couldn't immediately think of the answer in English! I had to actually stop and translate each word into English! I'd subconsciously switched to Spanish as my first language!