What does the different pronunciation mean in Chinese?

Syllables are not pronunciations. The pronunciation has tones, but the syllables have no tones. Mandarin Chinese has about 400 syllables and about 1,300 pronunciations.

ou first pronounces the sound o, and then gradually closes the lips to produce the sound u. The o is pronounced long and loud, and the u is pronounced short and vague.

iu is the combination of i and ou. When pronouncing it, pronounce i first, and then gradually transition the sound to u. The mouth shape of u is wider than the single vowel u, the tongue position is lower, and the loudness of u is louder than that of i.

Compound vowel:

ai is pronounced as a first, and this a is in a forward position than when a is pronounced alone. After pronouncing a, the tongue slowly rises, the mouth slowly closes, and stops when it reaches the tongue position of i. There is a sliding process from a to i.

ei pronounces the e sound first, and then slides towards i. When pronouncing e, the tongue position is further forward than when pronouncing e alone, and the pronunciation is louder.

ui is the combination of u and ei. When pronouncing it, the sound of u is pronounced first, followed by ei, and the shape of the mouth changes from round to flat.

Ao is pronounced as a first, with the tongue positioned further back than when a is pronounced alone. It should be pronounced long and loudly. Then the tongue is gradually raised, the mouth shape is closed and rounded, and a sound similar to u is made, which is soft. short.