Clark blinked as he didn't know the language that the man was speaking... and that was somewhat alarming. Given his gifts, his travels, he'd heard just about every language there was on the planet, including some that were dying out (though not if he had anything to say about it). As he was reasonably certain that it was a greeting, but it matched nothing he knew, he walked closer.

"Hello. I don't know that language, but greetings."

He signed the words as he spoke, wondering if perhaps the man was hearing impaired.