私たちはお茶を飲みながら喋っていた。

we; us

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

tea (usu. green); tea break (at work); tea ceremony

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to drink; to gulp; to swallow; to take (medicine); to smoke (tobacco); to engulf; to overwhelm; to keep down; to suppress; to accept (e.g. demand, condition); to make light of; to conceal

while; during; as; while; although; though; despite; in spite of; notwithstanding; all; both; as (e.g. "as always", "as long ago"); in (e.g. "in tears")

to talk; to chat; to chatter