What are the three consonant classes in Thai that determine the tone of a syllable?

• A Rising, level and falling
• B Short, medium and long
• C Open, closed and nasal
• D High, mid and low ✓

Thai consonants are divided into three classes ΓÇö high (sung), mid (klang) and low (tam) ΓÇö which interact with vowel length and syllable endings to determine one of five lexical tones.