What languages did Karl Marx speak and how well?

Question

Isaiah Berlin in Karl Marx: His Life and Environment comments on Marx efforts to learn Russian:

In order to do this he began to learn Russian; at the end of six months he had mastered it sufficiently to read sociological works1 and government reports which his friends succeeded in smuggling to London.

and on his reading in Russian, English and French

Finding on arrival that his English was inadequate, he set himself to improve it by making a list of Shakespeare’s turns of phrase: these he then learnt by heart. Similarly, having learnt Russian, he read the works of Gogol and Pushkin, care- fully underlining the words whose meaning he did not know. He had a sound German literary taste, acquired early in his youth, and developed by reading and re-reading his favourite works. To distract himself he read the elder Dumas or Scott, or light French novels of the day; [...]

He also apparently tried to study some other languages:

In his last ten years he began to acquire completely new languages: thus he tried to learn Turkish, for the ostensible purpose of studying agrarian conditions in that country; [...]

One could also expect that, having received good education, Marx had some knowledge of ancient Greek and Latin and perhaps French. It is less clear whether he could have known Hebrew, since his parents were converted to Christianity and he was raised as a Christian.

On the other hand, in a source less sympathetic to Marx, I have read that his economic work was out of date already at the time of its publication, since he had relied on the German translations of English documents, as after living in Britain for decades he hadn't mastered English. (Unfortunately, I cannot identify the text where I read this, though it was concerned more with history of mainstream economics than Marxism.)

My questions are:

• Which languages did Marx master?
• How well did he master them? Are there testimonies of him conversing in Russian or letters that he wrote in this language?

Remark
Interestingly, Friedrich Engels, Marx' closest collaborator and supporter, is often cited as a polyglot. The Wikipedia List of polyglots says about him:

Friedrich Engels (1820–1895), German political theorist. He knew many European languages, including German, English, Spanish, Portuguese, French, Italian, Russian, Polish, and Irish.

Answer 1

There is a difference between speaking a language and being fluent in it. In any case, Marx published books and articles in German, English and French. Engels writes that whole pages of “Das Kapital” were entirely in English and had to be translated into German for the published version. Marx’s letters to Engels swerve back and forth between German and English. Marx learned Russian and probably other European languages. He also commanded Greek and Latin. His PhD thesis is about the Greek philosophers Democritus and Epicurus, and he quotes the ancient sources in the original Greek and Latin.