Sure, but the landscape is something, namely an aggregate of particles. A thought in principle isn't its physical expression, but its information content, and it's represented in a human brain by some aggregate of particles. So no matter how you slice it, thoughts can only manifest within representations, and so calling language a representation of thought isn't some kind of dunk, because it also proves that human brains don't have thoughts.

It's not clear whether the information content of all possible human thoughts can be captured by language, but clearly at least some language expressions have the same information content as human thoughts.