Learn Romanian: Mă spăl pe degete.

Mă translates to "myself." In Romanian, when you wash a part of your body, you literally say "I wash myself." If you just used the verb spăl without mă, it would mean you are washing an object, like a car or the dishes.

Why does the sentence use pe (on)?

When washing body parts, Romanian uses the structure "to wash oneself on the [body part]." So mă spăl pe degete literally means "I wash myself on the fingers." You will see this with other body parts too, like mă spăl pe mâini (I wash my hands).

Why isn't there a word for "my" in this sentence?

In Romanian, you generally don't use possessive words like "my" with body parts if it is already clear who they belong to. Because you used the reflexive word mă (myself), it is completely obvious that you are washing your own fingers!

What is the singular form of degete?

The singular is deget (finger). It is a neuter noun, which means it behaves like a masculine noun in the singular (un deget) and a feminine noun in the plural (două degete).