What's the difference between 'determines' and 'influences'? I mean isn't that just a sliding scale? If a concept is incredibly difficult to formulate in a given language, could it not be said that the language has limited my thinking?
And, yes, if a concept is hard to express in a language that it, potentially, limits your thinking. If all thought is just language, then it may even bar thinking of concepts. But that gets into another debate, is language the key to thought, or is language an expression of thought. We can all probably conceive of things or maybe even have witnessed things which we are unable to articulate in many or all existing languages, but language expands or we adopt new languages (such as mathematics and calculus in particular to express physics). The precise motion of the planets could be explained in plain English, through complex circumlocutions. But calculus and its derived languages allow us to express this concept far more easily (even if just the English translation of the formulae and expressions, and not the precise notations used by physicists and mathematicians).
If an individual can't express a concept, how can you be sure they 'possess' that concept?
(answer might be found in bilinguals. There was an early saint from capadoccia who was grateful some of the more sophisticated greek heresies couldn't even be expressed in his language).