The Thai spelling is an approximate reading aid. Superscripts show the written Mandarin tones: 1 high/level · 2 rising · 3 low/dipping · 4 falling · 0 light/neutral. Mandarin and Thai tones are not identical. Keep neutral syllables short and light.

A third tone is often just low in connected speech. With two third tones together, the first normally becomes rising: 你好 is written nǐ hǎo but pronounced ní hǎo. Longer third-tone sequences depend on phrase grouping; listen to the whole sentence when audio is available.

Sounds Thai spelling cannot copy exactly: For ü (including the vowels in yǔn, xǔ, xū, yù, què), start with an “ee” tongue position and round your lips; do not turn it into Thai อู. For zh, ch, sh, r, keep the tongue slightly farther back; Mandarin r is not a rolled Thai ร. z/c start with a dental “ts” sound, while j/q/x are made farther forward than English “ch/sh.”

References: Education University of Hong Kong: tone changes · Yoyo Chinese: difficult pinyin sounds