You can learn new words by hearing them or reading them.
Learning new words involves several steps. Learning the word could be considered the final step. It means you know the word and can now use it.
Some people will learn a word the first time they see it or hear it.
Others take more time to internalize a word. There is no rule here.
When I read or hear a new word, I tend to repeat the word out loud.
Exposure is not some linguistic term for hearing/reading a new word.
Of course, we might say that some people are exposed to new words but don't bother to learn their meanings or how to say them.
That said, a word can have three basic "destinies":
But let's just say words, plural.
- You can forget them. That does happen.
- You remember them and the meaning but don't use them. That is called having a passive vocabulary.
- You remember them and use them: That is called having an active vocabulary.
Many people will, over the course of some number of years or their lifetime, encounter new words, look them up and never use them again. They become part of their passive vocabulary.
I think the idea you seem to be reaching for is:
- Learning a word or new words [end process]
- Being able to use those words either in writing or speaking.
Production of words is not a language learning term.
In language learning, one sees terms like increasing one's vocabulary, or enriching one's vocabulary. And the topic is usually called: vocabulary acquisition.