Accuracy refers to how correct learners’ use of the language system is, including their use of vocabulary, pronunciation and grammar.
In other words, accuracy is the correct use of tenses, verb forms, collocations and colloquialisms, among other things.
Fluency, on the other hand, refers to how well a learner communicates meaning, rather than how many mistakes they make in grammar, pronunciation and vocabulary.
In other words, the ease with which a learner can speak and how well they can communicate without pauses or hesitations, without needing to search for words or phrases, without having to consider the language of what they are about to say.
Read more: Accuracy And Fluency: What’s The Big Deal?