Learn Spanish (Latin America): El mesero sirve el pescado, pero nosotros pedimos el pollo. - The waiter serves the fish, but we order the chicken.

The verb for 'to serve' is servir. It is a stem-changing verb. This means the vowel in the stem (the e in 'serv-') changes to an i in most forms of the present tense. For he/she/it, servir becomes sirve.

If pedir (to order) is also an e-to-i stem-changing verb, why is it pedimos instead of 'pidimos'?

Stem-changing verbs have a special rule: the nosotros (we) form never changes its stem in the present tense. Even though the other forms change the e to an i, the 'we' form keeps the original vowel. Therefore, it stays pedimos.

Why does the sentence use pescado for fish instead of pez?

In Spanish, there are two different words for fish. Pez refers to a live fish swimming in the water. Pescado is used for fish that has been caught and is being prepared as food, which fits perfectly for a meal at a restaurant.

Doesn't pedir mean 'to ask'? Why is it translated as 'we order'?

Pedir literally means 'to ask for' or 'to request'. When you are at a restaurant asking the waiter for food, it naturally translates to 'to order' in English. It is the most common verb to use when ordering a meal in Spanish.