He casts *Comprehend Languages* in time to catch the Sindarin.
(It's normal to prepare Comprehend Languages when crossing the Wound alone, there's no knowing who you might meet. It's not worth it to prepare Share Language; that's what free slots are for, once you've established good intent.)
For now he'll repeat the man's greetings back to him (phonetically, and with a bad accent) and add his greetings in Taldane and Hallit. If they don't understand either of those, he'll mime that he can understand them but can't speak to them right now. Who knows, maybe one of them also has a Comprehend Languages, or something fancier.
(This is a common thing to mime in places where foreign adventurers are common, and may be harder to get across to people unused to the idea of one-way language spells.)
...Why aren't the halflings wearing any shoes? Is this a weird slavery thing? They look well-fed and uninjured, but Gord mentally settles into a more wary ready stance.