C'est
“C'est” means “is” or “it is” in “C'est quoi, ça ?” It introduces a question asking what something is, and the pattern “C'est quoi, ... ?” can be reused to ask what something is.
quoi
“quoi” means “what” in the question “C'est quoi, ça ?” Here it asks for the identity or name of the thing being pointed out. The pattern “C'est quoi, ... ?” is used to ask what something is.
ça
“ça” points to the thing being identified in “C'est quoi, ça ?” and can mean “this” or “that” depending on the context. It is useful at the end of a question when pointing to something.
là-bas
“là-bas” means “over there” in “C'est quoi, là-bas ?” The expression combines “là”, meaning “there”, with “bas”, meaning “down” or “below”, and the whole expression points to a place farther away. Use “là-bas” to indicate where something is located.
Qui
“Qui” means “who” in “Qui est cette personne ?” It asks for the identity of a person. The pattern “Qui est ... ?” is used to ask who someone is.
cette
“cette” means “this” before “personne” in “cette personne”. It identifies a particular person being pointed out or discussed. The pattern “cette” followed by a noun can identify one particular person or thing.
personne
“personne” means “person” in “cette personne”. It refers to the individual whose identity is being asked about. Use “personne” when referring to an individual.
Lequel
“Lequel” means “which one” in “Lequel est à toi ?” It selects one item from several possible items. The pattern “Lequel est ... ?” can be used to ask which item has a particular description or belongs to someone.
est
“est” means “is” in “Lequel est à toi ?” and “Celui-ci est à moi.” It links the item being discussed with information about it, and it is the dialogue form of “être” used for “is”. The pattern “X est ...” gives information about X.
à
“à” marks belonging in “à toi” and “à moi”. In the patterns “X est à toi” and “X est à moi”, it helps express who owns X. Use “à” before a person word in this ownership pattern.
toi
“toi” identifies the person addressed as the owner in “à toi”. The expression “à toi” means “belonging to you” in “Lequel est à toi ?” and “Celui-là est à toi.”
Celui-ci
“Celui-ci” means “this one” in “Celui-ci est à moi.” It combines “Celui”, which refers to the selected item, with “ci”, which indicates the one here or near the speaker. Use the whole expression to point out the nearer item among alternatives.
moi
“moi” identifies the speaker as the owner in “à moi”. The expression “à moi” means “belonging to me” in “Celui-ci est à moi.” Use “à moi” to state that an item belongs to you.
Celui-là
“Celui-là” means “that one” in “Celui-là est à toi.” It combines “Celui”, which refers to the selected item, with “là”, which indicates the one there or farther away. Use the whole expression to point out the more distant item among alternatives.