小声 literally means 'small voice' — 小 (xiǎo) means 'small' or 'little', and 声 (shēng) means 'voice' or 'sound'. Together, they form an adverb meaning 'quietly' or 'in a low voice'. It describes how something is said — not loudly, but softly and discreetly. This word is commonly used in everyday situations where lowering one’s voice is socially appropriate, such as in libraries, classrooms, hospitals, or when not wanting to disturb others.

Grammatically, 小声 typically appears before a verb (e.g., 小声说话, 小声问), or after the subject and before the predicate (e.g., 他小声说). It can also function as a predicate complement with 得 (e.g., 他说得小声). Unlike some adverbs, it is rarely used attributively (i.e., it doesn’t modify nouns directly). Its tone conveys politeness, caution, or intimacy — never rudeness or secrecy by itself, though context may imply those nuances.