Hopefully, everything adds up so far. Hundreds of Viets Cantonese, Holo, and Vietnamese are primary members of tribes or peoples referred to as Hundreds of Viets by the Han Empire in today central China, two thousand years back. Hundreds of Viets' languages have anywhere from 5 to 8 tones. Tone is an additional dimension to consonant and vowel. The syllable or sounds have consonant and vowel and pitch-level associated with it.
Different pitch can mean different words altogether.
Nasalized vowel and nasal constant vowel are two additional characteristics. Cantonese and Vietnam, sounding quite similar just as Spanish and Italian do, can be heard in Hollywood movies. It is as communicable as speaking French to an American. The commonalty of Cantonese, Holo, and Vietnamese languages and cuisine within Hundreds of Viets is analogous to Israelis and various Arabs within Semites. Despite, each has its very different fate through history.