小声で話してください。

low voice; whisper

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

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

to give; to confer; to bestow; to kindly do for one; to oblige; to favour; to favor