How do you say "I'm speaking Chinese because…" in Mandarin?

I want to say, "I’m speaking Chinese because… 我不要我的妈妈听到我们." Or "I’m speaking Chinese because… 我要练." (I’m not sure if that’s right, but whatever.) xD I would appreciate if you could answer in pinyin, I don’t know a lot of characters, only basics. Edit: If you speak more than one language, …