Fluency in language learning is the ability to use the spoken or written form of the language to communicate effectively. While fluency does require a reasonable knowledge of vocabulary and grammar, the language produced does not need to be flawless as long as you are able to be clearly understood. In contrast, accuracy refers to the production of grammatically correct spoken or written language. While it is important to learn the correct forms of the language, accuracy does not guarantee the ability to communicate fluently.
Often the hardest part of a language teacher’s job is finding the right balance between fluency and accuracy related teaching in the classroom, as both are equally important. However, the student’s reason for studying the language will sometimes dictate the balance to some extent. For example, adults who are learning English for non academic reasons are likely to be more concerned with fluency, while young learners studying for exams are more likely to be concerned with accuracy.