The way I have heard it said most often is "Nihongo ga jouzu desu" (My Japanese is good) or "Nihongo ga perapera desu" (My Japanese is fluent). However, if you need to ask this question, it most likely does not apply to you.
Arsène Wenger is known to fluently speak four languages: French, English, German, and Japanese.
Fluently: Danish, Italian, Spanish and English. Can understand Swedish and Japanese. Not sure of his efficiency in Japanese and Dutch.
She can speak Japanese (of course), French, English. But I think she can't speak F and E fluently, just basic parts.
matemashita means matemashita in Japanese in English it means "i waited"
You could say "No puedo hablar español con fluidez."
habla con fluidez el amor
If you are "fluent" in a language you speak it like you would your mother tongue, you speak it fluently.
There are gnomes that speak German fluently because they are german. Or they simply studied it.
It would take a person of likely impossibly extreme genius to learn to speak Japanese fluently in a day.
"I speak French fluently" translated into French is: Je parle couramment français / Je parle français couramment (both correct and common)
In my understanding maybe they wanted to say bad in our English if we didn't speak fluently in English or if we didn't speak correctly and wrong grammar.
Hiromu Arakawa, the manga artist known for works such as "Fullmetal Alchemist," is primarily a Japanese speaker. While she may have some proficiency in English, there is no confirmation that she is fluent in the language.