The phrase "acquire fluency" is correct and commonly used in written English.
It means to develop or gain the ability to speak or write a language easily and accurately. You can use it when discussing language learning or someone's proficiency in a language. Here is an example: "Studying abroad in Spain helped him acquire fluency in Spanish, making him a valuable asset in our international business dealings."
To prosper in the information age, it is now necessary to acquire deeper understanding, to acquire fluency (National Research Council, 1999).
Boxing and drumming are rhythmic languages, and it's hard to acquire fluency in any language you come to in adulthood.
Heian women were traditionally excluded from learning Chinese, the written language of government, but Murasaki, raised in her erudite father's household, showed a precocious aptitude for the Chinese classics and managed to acquire fluency.
As some of the lowest but also the hungriest in the art food chain, interns have much to gain from acquiring fluency in it.
In the hospital he acquired fluency in Italian, which would turn out to be a great help in writing "Il Duce: The Life of Benito Mussolini" (1962), "Garibaldi and His Enemies" (1965) and "Rome: The Biography of a City" (1985).
He also acquired fluency in multiple languages along the way and became a writer.
Conroy's native language was of particular value to the Duchess because she had not yet acquired fluency in English.
According to one theory, children don't "learn" to write; rather, they "acquire" writing fluency through inputs of pleasure reading in the same way that we acquire our native language by being inundated in it.
The language Gonsales encounters on the Moon bears no relation to any he is familiar with, and it takes him months to acquire sufficient fluency to communicate properly with the inhabitants.
She was also quietly acquiring a fluency in reading Norwegian and then Swedish.
This was where Anne first attended university, using her rapidly acquired linguistic fluency to study for a postgraduate degree in English literature through Danish.
