Use of acuerdo, me acuerdo, and me acuerdo de

It looks like there are examples of all three of these constructions used, seemingly interchangeably to me. Is there a rule on when to use the reflexive, and when to use the “de”, for example, when saying “I remember her” -- “Acuerdo a ella” - “Me acuerdo a ella” - “Me acuerdo de ella”?

¡Hola ULCardFan!

Thanks for your question! I'll dive right into the answer.

Acordar by itself generally means “to agree” or “to set” (in terms of a date or appointment); it can't be used to mean “to remember.” To get that meaning, you need to have a reflexive pronoun and follow the verb with the preposition de. It's easiest to memorize it as one full construction: acordarse de = “to remember.” Therefore, “(I) remember her” would be Me acuerdo de ella. As a second example, “(I) remember that day” would be Me acuerdo de ese día.

Note that some native Spanish speakers who are speaking casually will drop the de before subordinate clauses (i.e. phrases that can't stand on their own as complete sentences). That means that for the sentence “I don't remember her name,” you may hear people say “No me acuerdo cómo se llama” instead of No me acuerdo de cómo se llama. 

I should also mention that there are actually two “remembering” verbs in Spanish, and you may also be thinking of the second one: recordar. You can use acordarse de and recordar pretty interchangeably; recordar means “to remember / to recall.” This verb isn't reflexive and it isn't followed by a preposition (unless a personal a is needed). So, using it, “(I) remember her” would be La recuerdo a ella and “(I) remember that day” would be Recuerdo ese día.

I hope that this has been helpful! Do let me know if you still have any questions here.

Saludos,

Liss