How do tones distinguish words in Hmong-Mien languages?

In Hmong-Mien languages, tone is a fundamental feature that distinguishes words, contributing as much to their identification as consonants and vowels do. Because these languages are tonal, every word carries a distinctive tone that serves to differentiate it from others.12

These tonal systems are often complex:
* Pitch Distinctions: Languages may utilize a variety of level tones (spoken at different pitches) and contour tones (which change pitch during articulation). Some languages, such as Longmo Bunu and Zongdi Hmong, feature as many as 12 tonal contrasts.1
* Voice Quality: In addition to pitch, some tones are characterized by specific voice qualities, including "breathy," "whispered," or "creaky" tones.1
* Grammatical Role: Tones in Hmong-Mien languages are used almost exclusively to differentiate words; they only rarely serve a grammatical function.2

While consonants and vowels provide the basic structure of the monosyllabic words common to this family, the specific tone assigned to each syllable is essential for determining its meaning.1