Learn Spanish (Latin America): ¿Tú comienzas el proyecto temprano?

Comenzar (to begin) is a stem-changing verb. In the present tense, the e in the middle of the word changes to ie for almost all pronouns (except nosotros). So for tú, the stem comenz- becomes comienz-, giving us comienzas.

Where is the word for 'Do' in this question?

Spanish doesn't use helper words like 'do' or 'does' to make a question. You simply take the normal statement (Tú comienzas, which means 'You begin') and put question marks around it.

I thought 'to begin' was empezar. Can I use that here instead?

Yes! Comenzar and empezar are synonyms and can be used interchangeably. Since empezar is also an e to ie stem-changing verb, the sentence would be ¿Tú empiezas el proyecto temprano?

Do I need to include tú at the beginning?

No, it is entirely optional. Because the verb ending -as in comienzas already tells us that 'you' are the one beginning the project, you can just say ¿Comienzas el proyecto temprano? Including tú just adds a little extra emphasis.