Quote Originally Posted by M.Vonok View Post
Would this be another example of the genitive case with negation, or does знать use the Genitive case with direct objects?

невозможно говорить на любом языке, если не знаешь слов....

Also is it common with transitive verbs to apply the Genitive case to a negated direct object, I see this quite often when I read?
The genetive case with negations implies absense or lack of something.

Жизни не хватит - here it implies that one life won't be enough for a particular purporse - lack

Also, знать means to have knowledge, have somehing stored in your mind etc, so it requires the genetive case after it if if you use it negatively.

Я не знаю слов - Look at that like this --- The words are absent from my mind or I don't have the words stored in my mind - absence

However, you still can say я не знаю слова, but this one would sound more general, like you don't know words at all

But, other verbs may not imply having something with their meanings. So they don't take the genetive case for their objects if you use the verb negatively.

For example:

Я люблю стол - Стол is in accusative
Я не люблю стол - Стол is still in accusative

That's because любить doesn't mean to have love but to be in love