Russell's theory of descriptions revolves around the definite and the indefinite articles of the English language in an attempt to solve some of the basic but serious problems in philosophy of language.
Why was this theory taken seriously at all?
(a) There are natural languages that don't have articles at all, like Russian, among lots of other languages.
(b) In these articleless languages same problems can be posed without any difference in meaning whatsoever.
(c) Even if each and every language of the world had articles, it is logically possible that there could be languages that didn't have them and met criterion (b).
The theory therefore seems to me entirely English-centered. In this light, Russell seems to be a linguist interested in how the English language functions, not how language (in the abstract sense of the word) works, which is what a philosopher of language should strive for ultimately.