It is widely known that Maude's English translation of War and Peace was approved by Tolstoy himself. How did Tolstoy approve it, and did he know and speak English?
Tolstoy was born into the Russian aristocracy and thus had the benefit of paid tuition as a young man. He was interested in languages and so, given the opportunity to learn them, he did. In fact he was a polyglot and was fluent in a number of other languages including English, French and German. He was able to read in a number of other languages and his library was multilingual. Indeed he was enthusiastic about the work of British writers Laurence Sterne and Charles Dickens, which he read in the original.
The Maudes were personal friends and admirers of Tolstoy, having met him during their time living in Russia. They continued a regular correspondence after the Maudes returned to England and began translating his works, with his authorisation and approval. As part of this work, Aylmer Maude continued to make occasional visits to see Tolstoy in Russia. So, given that he could speak and read in good English and was in frequent contact with his translators, there was no great barrier to Tolstoy giving his blessing to their work.
- Encyclopedia Britannica
In his critique of Shakespeare, Tolstoy wrote:
For a long time I could not believe in myself, and during fifty years, in order to test myself, I several times recommenced reading Shakespeare in every possible form, in Russian, in English, in German and in Schlegel's translation, as I was advised.
It would seem clear, then, that he was able to read and understand English at a fairly high level.