"Thank both of you"

Is there a trace first person pronoun before the utterance "thank you", making it shorthand for "I/we thank you"?

A ramification of this question is an expression of gratitude I just heard that didn't sit right with me:

Thank both of you for coming.

This sounded strange, almost like my intuition was to interpret it as a command for someone to thank themselves (?). My intuition would have preferred

Thank you both for coming.

I convinced myself that the former would sound acceptable if there is an implicit first person pronoun preceding every "thank you" because "I thank you both for coming" is perfectly natural. Is there a trace there or is "thank you" an atomic phrase with some other underlying syntax (or none at all)?

Thank all of you!

Solution 1:

You're right that "thank you" could be used in either a singular or plural setting. So "thank you both" and "thank you, Raj" both work.

But "thank you" is a phrase, a shortened form of "I thank you" (http://www.etymonline.com/index.php?term=thank+you); to split it and try to use its component parts as if they were joined -- and as if they were both nouns -- is misguided. As soon as you split "thank" from "you", the words become separate entities.

"Thank" is a verb, which is why, as you suggest, it demands a subject ("I" in the first person) when not used as a directive (e.g. Thank your mother). That's one reason why "Thank to both of you" doesn't work (i.e. is grammatically incorrect), and why "I thank both of you" does.

"Thanks" is a noun, so "Thanks to both of you" would be another grammatically correct option here.

Solution 2:

Thank you both for coming.

is the easy, natural way to express this.

I thank you both for coming.

sounds very stilted and formal.