靴のサイズはどれくらいですか。

shoes; boots; footwear; footgear

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

size

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

which (of three or more); whichever; any; well; now; let me see

approximately; about; around; or so; to (about) the extent that; (almost) enough that; so ... that ...; at least; as ... as ...; like

be; is

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way