なにか・なにも

なにか and なにも both refer to things in an unspecified way, but they are used with opposite polarities. なにか is used when the speaker affirms that there is or will be some thing, often in questions or positive statements (e.g., Do you have something?). なにも is used with negative verbs to mean “nothing” or “not anything,” emphasizing the absence of any thing. In everyday speech, 何か can appear in questions, requests, or expressions of desire, while 何も occurs almost exclusively with negative verbs or constructions. Note: 何か can also imply “some kind of” in broader contexts, while 何も strictly negates. Usage often hinges on whether the verb is positive or negative, and whether you’re asking, offering, or denying existence of something.