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How Thai Tone Rules Work

Thai doesn't use tone marks directly. The actual tone depends on three factors: consonant class + syllable type + tone mark. Here's the system behind the rules.

Thai Tone Rules Summary

Thai determines tones using 3 factors:

  1. Consonant class (high, mid, or low)
  2. Syllable type (live or dead)
  3. Tone mark (none, mai ek, mai tho, mai tri, or mai chattawa)

These three factors combine to produce one of Thai's 5 tones: mid, low, falling, high, or rising.

The Three-Factor System

Thai tone rules look complicated until you see the pattern. Three factors, applied consistently.

1

Initial Consonant Class

High, Mid, or Low class (based on historical phonetic features)

+
2

Syllable Type

Live (ends in long vowel or sonorant) vs. Dead (ends in short vowel or stop)

+
3

Tone Mark

No mark, Mai Ek, Mai Tho, Mai Tri, or Mai Chattawa

=
→

Actual Tone

One of the five tones you actually speak

The Three Consonant Classes

Thai's 44 consonants are divided into three classes that determine tone behavior.

High Class

อักษรสูง 11 consonants

Historically, these were voiceless aspirated consonants. They affect tone in specific ways.

ขฃฉฐถผฝศษสห
Basic Rule: With no tone mark: Rising tone (live syllables) or Low tone (dead syllables).

Mid Class

อักษรกลาง 9 consonants

The "neutral" consonants. Originally voiceless unaspirated. All four tone marks work with mid class.

กจฎฏดตบปอ
Basic Rule: With no tone mark: Mid tone (live syllables) or Low tone (dead syllables).

Low Class

อักษรต่ำ 24 consonants

Historically voiced or voiced aspirated. The largest class with 24 consonants.

คฅฆงชซฌญฑฒณทธนพฟภมยรลวฬฮ
Basic Rule: With no tone mark: Mid tone (live syllables), High tone (short dead syllables), or Falling tone (long dead syllables).

Memory Tip

Mid class (9 consonants) = the most flexible, works with all 4 tone marks
High class (11 consonants) = only uses Mai Ek and Mai Tho
Low class (24 consonants) = the largest group, only uses Mai Ek and Mai Tho

Tone Marks and Their Effects

The same tone mark produces different tones depending on the consonant class.

Tone Mark
Symbol
Mid Class
High Class
Low Class
Example
Mai Ek ไม้เอก
่
Low tone
Low tone
Falling tone
น่า nâa
Mai Tho ไม้โท
้
Falling tone
Falling tone
High tone
ค้า kháa
Mai Tri ไม้ตรี
๊
High tone
(not used)
(not used)
ป๊ะ pá
Mai Chattawa ไม้จัตวา
๋
Rising tone
(not used)
(not used)
ป๋า pǎa
Important: Mai Tri (๊) and Mai Chattawa (๋) only work with mid-class consonants. Low and high class consonants only use Mai Ek (่) and Mai Tho (้).

Live vs. Dead Syllables

Syllable type affects the default tone when no tone mark is present.

Live Syllables

คำเป็น (kham bpen)

End in a long vowel or a sonorant consonant (ม, น, ง, ย, ว, ร, ล)

มา maa ends in long vowel
คน khon ends in น (sonorant)
Default tones (no mark): Mid (mid class), Rising (high class), Mid (low class)
Dead Syllables

คำตาย (kham dtaai)

End in a short vowel or a stop consonant (ก, บ, ด, ป, ต, ค, พ, ท)

จะ ja ends in short vowel
พบ phop ends in บ (stop)
Default tones: Low (mid/high class), High or Falling (low class, depends on vowel length)

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