What does orwell mean when he writes about the decline of language?

He said that the issues of vague writing is described as been decayed, which is major factor that lead to the collapse in the society.

Explanation:

Orwell says that the decline of language was self-perpetuating.

He states that it is easier to think with poor English language  because it is on  decline, and as the language declines, Thoughts that are foolish becomes even easier, simpler, reinforcing the original cause.  he says its the same thing as regards to what is happening to the English language.

He also described the problem of vague writing as decay and slovenliness that has lead to decline of languages and can lead to general collapse in the society.