Learn Portuguese (Portugal): O cão gordo come muito.

In Portuguese, adjectives usually come after the noun they describe. So, instead of placing the describing word first like in English, the structure is dog fat (cão gordo).

Would gordo change if we were talking about a female dog?

Yes! Adjectives must match the gender of the noun they describe. Because cão is masculine, we use the masculine form gordo. If we used the word for a female dog (cadela), the adjective would change to the feminine form, making it a cadela gorda.

Does muito need to change its ending to match the dog, just like gordo does?

No, because here muito is an adverb meaning a lot. It describes the action of eating (come), not the dog itself. Words that describe verbs do not change their endings. Muito only changes to muita, muitos, or muitas when it means much or many and describes a noun.

Why does the sentence use come instead of como?

Come is the form of the verb comer (to eat) used for he, she, or it. Since the dog is the one eating, we use this third-person form. Como is the form used for I, so como muito would mean I eat a lot.