いったん話し始めると、彼女を止めることは出来ない。

once; for a moment; temporarily; one morning

to talk; to speak; to converse; to chat; to tell; to explain; to narrate; to mention; to describe; to discuss; to speak (a language)

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

she; her; her; girlfriend; sweetheart

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 stop; to turn off; to park; to prevent; to suppress (a cough); to hold back (tears); to hold (one's breath); to relieve (pain); to stop (someone from doing something); to dissuade; to forbid; to prohibit; to notice; to be aware of; to concentrate on; to pay attention to; to remember; to bear in mind; to fix (in place); to fasten; to tack; to pin; to nail; to button; to staple; to detain; to keep in custody

thing; matter; incident; occurrence; event; something serious; trouble; crisis; circumstances; situation; state of affairs; work; business; affair; after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to; nominalizing suffix; pretending to ...; playing make-believe ...; alias; aka; nickname; alternative name; also known as

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

to be able (in a position) to do; to be up to the task; to be ready; to be completed; to be made; to be built; to be good at; to be permitted (to do); to become intimate; to take up (with somebody); to grow; to be raised; to become pregnant