I've just seen the size of the dictionary for the language I want to learn. You don't have to learn the dictionary to be fluent. Most languages have a core vocabulary of a few thousand words, which form the basis for most communication. Learn the 2000 most common words in English and you can cope with basic conversation. A fluent speaker will know about 7000 words.
Words are like people and tend to associate often with a small group of other words.
So you have to learn who are the 'friends' of the word you have just learned. You will often find black with eye , look , out , magic , humour , person , coffee , mood and blue . You will rarely find black with table , car , cake or pen . That does not mean that talking about a black car is wrong but it does mean that it would be useful to know the meaning of black humour . Modern dictionaries are a great help with this.