I've just starting learning Japanese last week.
And I'm playing a video game in Japanese. One of the characters said: "礼を言う" (rewoiu) just by itself. The English translation was "Thank you."
But I didn't recognize this as any version of "thank you" I had heard before.
The translation I get when searching is: "Say thanks". But this is basically just a non-past verb. Can you use non-past verbs by themselves usually?
Anyways, can someone help enlighten me on this? Does "say thanks" in japanese also mean "thank you"? If so, when is it appropriate to use this over other common forms of thank you; what's the difference between this and "arigatou"?