How do you say I only speak french in spanish?

There are a couple of ways to say "I only speak French" in Spanish:

Formal:

* Solo hablo francés. (This is the most direct and literal translation.)

Informal:

* Yo sólo hablo francés. (This is a bit more emphatic and adds "yo" for emphasis.)

* Habló francés nada más. (This translates to "I speak French, nothing more.")

You can also use the word "únicamente" to emphasize "only," like:

* Únicamente hablo francés. (This translates to "I only speak French.")

The best option for you will depend on the context and the level of formality.