On a very basic level, languages have two key components: vocabulary, the actual words, and grammar, which is the set of rules determining how the words are strung together to make sentences. And you encounter language in the form of the so-called four skills: listening, speaking, reading and writing.
You certainly can’t get away from the vocabulary; some language courses avoid too much grammar, and concentrate instead on certain situations, like buying a ticket or ordering a meal. Listening and speaking are the most important skills for most people; some courses don’t offer much reading, and may leave out writing altogether.
It all depends what you want.