A Dilemma

I've heard it said that when you sing, you pray twice. I've always interpreted this to mean that both the words you sing and the fact that you are singing are prayful.

For the last several weeks, I've been going to Xhosa-language church services. It's gotten to the point where I can sing along (sort of) on some of the hymns and choruses. But I don't know what any of the words mean. If I don't know what I'm singing, am I praying once or twice?