He ate all the cookies.What is the function of “se” in this sentence? I get confused because sometimes the indirect object pronoun appears before a non-reflexive verb and sometimes it does not and I’m confused on the rules of when I should use it.
This se is part of ‘comerse’, which means ‘to eat up’. I think it’s better to think of this as a different verb from ‘comer’.
You could try (*) ‘le comió las galletas’ and see it doesn’t work, therefore this isn’t the usual ‘comer’. But this rule isn’t very good, because comer can take an indirect object in many cases. ‘Te está comiendo el coco’, ‘El niño no me come’, etc.
It may be that the only way to parse these sentences is to be aware that certain verbs have ‘-se’ variants and to think about which meaning makes the most sense in each case. Like ‘estaba pelando las patatas y me corté’ = cortar with indirect object, but ‘quería sacarla a bailar pero me corté’ = cortarse. ‘Me crecen los enanos’ = crecer with indirect object, but ‘Me crezco ante la adversidad’ = crecerse. And so on.