Is it reasonable to claim that a particular language is more superior than another in terms of the way it captures reality, for instance, by having a wider vocabulary than others?

Sure it is. Obviously, one would have to defend any such claim with specific examples in mind, but here's one that is now famous among philosophers.

For a long time, people used and made decorative items made from "jade." But then, chemical analysis showed that what people were calling "jade" was actually two distinct materials, which are now called "jadeite" and "nephrite." Both are still generically called "jade," but sophisticated buyers now know well that there are differences between these two materials, and these differences may have an impact on the value of artifacts made from each material.

Here's the point: a language that simply has the term "jade" in it will not be as effective for describing the world as a language that has both "jadeite" and "nephrite" in it. So there's your answer.

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