How do you say I speak Farsi in Farsi?

There are a few ways to say "I speak Farsi" in Farsi, depending on the context and level of formality:

Formal:

* من فارسی صحبت می‌کنم (Man Farsi sohbat mikonam) - This is the most formal way to say it.

* من به زبان فارسی صحبت می‌کنم (Man be zabān-e Farsi sohbat mikonam) - This adds the word "language" for even more formality.

Informal:

* من فارسی حرف می‌زنم (Man Farsi harf mizanam) - This is a more informal way to say it.

Even more casual:

* فارسی بلدم (Farsi baladam) - This literally means "I know Farsi," and it's a very casual way to express that you speak the language.

You can also use the word "fluent" in Farsi if you want to emphasize your level of proficiency:

* من به زبان فارسی مسلط هستم (Man be zabān-e Farsi mosallet hastam) - This means "I am fluent in Farsi."

The best option for you will depend on the situation and who you are talking to.