1.
Someone who is ~ in a particular language, can speak the language easily and correctly. You can also say that someone speaks ~ French, Chinese, or some other language.
She studied eight foreign languages but is ~ in only six of them...
He speaks ~ Russian.
ADJ: oft ADJ in n
fluency
To work as a translator, you need fluency in at least one foreign language.
N-UNCOUNT
~ly
He spoke three languages ~ly.
ADV
2.
If your speech, reading, or writing is ~, you speak, read, or write easily, smoothly, and clearly with no mistakes.
He had emerged from being a hesitant and unsure candidate into a ~ debater.
ADJ
fluency
His son was praised for speeches of remarkable fluency.
N-UNCOUNT
~ly
Alex didn’t read ~ly till he was nearly seven.
ADV: ADV with v