Low-class partners: ค ช ซ ท พ ฟ ฮ ธ ภ

Most high-class letters have a low-class partner with exactly the same sound:

• ขkǎw and คkaw: k
• ฉchǎw and ชchaw: ch
• สsǎw and ซsaw: s
• ถtǎw and ทtaw, ธtaw: t
• ผpǎw and พpaw, ภpaw: p
• ฝfǎw and ฟfaw: f
• หhǎw and ฮhaw: h

Why two letters for one sound? Centuries ago they really were different sounds. The sounds merged, the spelling stayed, and the old difference survives as tone: ขาkǎa (leg) but คาkaa (stuck).

The low class is simply every letter that isn't mid or high: these partners, the seven humming letters from lesson 4 and a few rare ones.

Low-class tones without a tone mark

• live syllable: mid: ชาchaa (tea), ทางtaang (way)
• dead, long vowel: falling, marked with a circumflex (â): พูดpûut (speak), ชอบchâwp (like), มากmâak (very)
• dead, short vowel: high: coming with the short vowels in lesson 10

The full table without tone marks

• mid class: live mid · dead low
• high class: live rising · dead low
• low class: live mid · dead with a short vowel high · dead with a long vowel falling

A reading routine

1. What class is the first consonant?
2. Is the syllable live or dead?
3. If it's dead and low class, is the vowel short or long?

Try it on ลูกlûuk (child): ลlaw is low class, the syllable is dead (it ends in k), the vowel is long, so the tone falls.

One oddity to remember: in ไทยtai (Thai) the final ยyaw is silent, an old spelling.

Typical mistake: giving มากmâak (very) a low tone, as if มmaw were mid class. Without a tone mark, low-class letters never have the low tone.