Formal:
* "I am fluent in French." This is the most formal way to say it.
* "I speak French." This is also a formal way to say it, but it is less specific about your level of fluency.
* "I have a good command of French." This is a more nuanced way to say it, suggesting that you are proficient but may not be completely fluent.
Informal:
* "I can speak French." This is a more casual way to say it.
* "I know how to speak French." This is a more direct way to say it.
* "I'm pretty good at French." This is a more conversational way to say it, suggesting that you are comfortable speaking the language.
You can also use phrases like:
* "I understand French."
* "I can read and write French."
The best way to say it depends on the situation and your own level of confidence in your French skills.