The terms "acquisition" and "learning" are often used interchangeably in relation to a second language, but there is a clear distinction between them. Stephen Krashen's Acquisition - Learning hypothesis states that while acquisition is a subconscious system, learning is an explicit and conscious process. To put this distinction into context, native speakers may have a tacit knowledge of language, but they focus on meaning to interact with other speakers. However, non-native speakers or second language learners have a conscious knowledge of their target language and rely on grammar rules to perform orally and in writing. The L2 learner's conscious use of grammar rules explains why very few adult learners, if any, achieve native-like proficiency in their second language. Acquisition, in this sense, mirrors the subconscious process children go through while acquiring their first language.
To read the entire post, please go to my blog on language and linguistics here:
https://jilaniwarsi.blogspot.com/2017/05/acquisition-vs-learning.html