Originally Posted by
Wikipedia -Fluency Language fluency is used informally to denote broadly a high level of language proficiency, most typically foreign language or another learned language, and more narrowly to denote fluid language use, as opposed to slow, halting use. In this narrow sense, fluency is necessary but not sufficient for language proficiency: fluent language users (particularly uneducated native speakers) may have narrow vocabularies, limited discourse strategies, and inaccurate word use, and may be illiterate. Native language speakers are often incorrectly referred to as fluent.
In the sense of proficiency, "fluency" encompasses a number of related but separable skills:
Reading: the ability to easily read and understand texts written in the language;
Writing: the ability to formulate written texts in the language;
Comprehension: the ability to follow and understand speech in the language;
Speaking: the ability to speak in the language and be understood by its speakers.
To some extent, these skills can be separately acquired. Generally, the later in life a learner approaches the study of a foreign language, the harder it is to acquire auditory comprehension and fluent speaking skills – however, the Critical Period Hypothesis is hotly debated. Reading and writing a foreign language are skills that can be acquired more easily after the primary language acquisition period of youth is over, however.