OK: First, we have "ci" direct and indirect object pronoun of third person plural. For subject we use "noi" and for object "ci". Also reflexive pronoun, same person (Noi ci siamo divertiti). Also used at the place of "qui" or "la",or "lì) : Ci vengo spesso; ci abito; che ci fai? (I come here (there) very often, I live here (there) What are you doing there(here). The exact meaning depends on the context. Ci can also be placed instead of "a quello" "a ciò": Ci penso io; Non ci credo. (I'l take care of that; I don't believe in such a thing) Together with the verb stare as a phraseological verb with the meaning of "I'm able", "I'm willing to":" Io ci sto !" (I'm ready, I agree) Si : without the accent is a reflexive pronoun third person singular and plural. "Si sono vestiti in fretta", Si è pettinato con cura". Also present in non-personal constructions : "Qui si mangia bene!". With the accent can also be a contraction of "così", mostly in letterary and formal constructions: ""sì del cammino e sì de la pietate che ritrarrà la mente che non erra" (Dante DC c II). For now, that's enough. The proper use of "ci" and "ne" are the most critical aspects of the Italian language learning

they have lots of meanings but mainly they are pronouns. perhaps, it could be more useful to look at http://oxfordparavia.it/lemmaIta5776 and http://oxfordparavia.it/lemmaIta26607

A, B, C (ci) alfabeto italiano: pronuncia or A (ei), B (bi), C, (si) english alphabet: phonetic alphabet. ..all right baby ciao fil..