To "observe how we use words" is to make statements, in ordinary language, about the role, function, effects, and context of expressions. But in doing this, the concepts and presuppositions of that ordinary language are taken for granted and insinuated as the only possible view [...] It is true that certain things may be said in favour of ordinary language. It would not be in use, and it would not have survived were it not wholly without merit. But this argument, as in politics where it is often used to buttress conservatism, proves fairly little. Very silly and undesirable things often survive, and neither society nor language is such a tightly integrated whole as would disastrously suffer from alteration of some one part. (pp. 195-197)For Gellner, contra Wittgenstein, ordinary language can be improved upon by the very activity of reflecting on it, leaving a positive role for philosophy after all:
[T]here are many language games which become unworkable when properly understood: where self-consciousness not merely does not "leave everything as it is" but simply necessitates change. Many "conceptual systems", in primitive societies and in advanced ones, contain confusions and absurdities which are essential for their functioning. To lay them bare is to make such a framework unworkable. (p. 206)The notion of improving language (my paraphrase) would need a lot more working out than I see in this book, but presumably means something like "make the concepts and presuppositions underlying language use more internally coherent and in better accord with non-linguistic experience."
Such a standard would not necessarily imply that one language can be superior to another. For one thing, while such concepts and presuppositions certainly play a role in language use, they don't seem to be critical to the definition of a language; you can change them and leave the language sufficiently intact to be mostly understood by speakers who have retained the old ones. A single language has room for many different kinds of language use.
However, it would suggest a potentially interesting alternative to a purely descriptive approach to linguistics. If Linguistic Philosophy was the effort to identify ways in which attention to ordinary native speakers' usage might correct misunderstandings embedded in philosophical thought, would Philosophical Linguistics be the effort to identify ways in which attention to philosophical thought might correct misunderstandings embedded in ordinary native speakers' usage?