Writing the high consonants

The eleven letters

Seven of them are everyday letters: ข, ฉ, ถ, ผ, ฝ, ส and ห. ฃ is obsolete; modern spelling uses ข in every word that once had it. ฐ, ศ and ษ spell words from Pali and Sanskrit, such as รัฐ rat (state), ศึกษา sueksa (education) and ภาษา phasa (language), so you will meet them often in formal Thai even though they add no new sound.

Their sounds

Every high-class letter is breathy. ข, ฉ, ถ and ผ are the aspirated kh, ch, th and ph: say the k of “kit” or the p of “pin” with a clear puff of air. ฝ is f, ศ, ษ and ส are s, and ห is h. The th and ph of romanised Thai are always these aspirated stops, never the th of “thin” or the ph of “phone”.

Each common high-class sound has a low-class twin with exactly the same sound: ข and ค, ฉ and ช, ถ and ท, ผ and พ, ฝ and ฟ, ส and ซ, ห and ฮ. The twins exist for the tones: between them, a high and a low letter can spell all five tones on one sound.

At the end of a syllable, ข is read k and ฐ, ถ, ศ, ษ and ส are read t, unreleased like every Thai final stop: สุข sùk (happy), รถ rót (car), ประเทศ prathêet (country). ฉ, ผ, ฝ and ห do not end syllables.

How to write them

• Start at the head. Every high-class letter begins at its loop and runs in one stroke where it can.
• Watch the tails. ฝ, ศ and ส end with a tail that rises above the line; ฐ has a tail that hangs below it, which fonts leave off when a vowel sign goes underneath.
• Learn the families together. ข and ช differ only by the rising tail of ช (which is low class); ฃ is ข with a notch in its top. ผ and ฝ differ by the tall tail of ฝ, and พ and ฟ, their low-class look-alikes, differ in the same way. ส is ล with a tail; ศ ends in the same tail on a different body.
• ถ has a loop; ก has none. ถ starts from a small loop low on its left side, which is what sets it apart from ก. ภ, a low-class letter, shares the loop, so compare ถ and ภ side by side at a large size.

Writing a pair in one sitting, at a large size, teaches the difference faster than writing each letter alone. On the letter pages you can compare any letter across every font in the collection, which shows which strokes stay the same whatever the style.

Ways to remember them

• The class sentence. ผีฝากถุงข้าวสารให้ฉัน, phi fak thung khao san hai chan: “a ghost left a bag of rice with me”. Its first letters are ผ ฝ ถ ข ส ห ฉ, the seven common high-class letters. The rest are ฃ (obsolete) and the three loan letters ฐ ศ ษ.
• Breath means high. If a letter stands for a puff of air or a hiss and is not one of the low-class twins, it is high class. The low-class twins are the letters you are more likely to meet first in very common words: ค, ช, ท, พ.
• The name words: ข ไข่ (egg), ฉ ฉิ่ง (cymbals), ถ ถุง (sack), ผ ผึ้ง (bee), ฝ ฝา (lid), ส เสือ (tiger), ห หีบ (chest).

What the high class does to tones

High-class letters take only mai ek and mai tho, and spell three tones:

The mid and high tones on kh are spelled with the low-class twin: คา khaa (to be stuck) is mid and ค้า kháa (to trade) is high. That division of labour is the reason Thai keeps two letters for each of these sounds.

A silent ห extends the high class to sounds it does not have. Written in front of ง, ญ, น, ม, ย, ร, ล or ว, it is not pronounced but makes the syllable follow the high-class rules: หมา mǎa (dog), หนาว nǎao (cold), ใหญ่ yài (big). The tone rules have the whole system.

Practice that works

1. Read the high and low twins in pairs, out loud: ขา and คา, สา and ซา, ผา and พา. The consonant sound is the same; only the tone changes.
2. Write the families in one line each: ข ฃ ช ซ, then ผ ฝ พ ฟ, then ล ส ศ.
3. Collect words with a silent ห as you meet them; they are common (หนึ่ง, one; หนังสือ, book; หลาย, many) and each one is a small tone lesson.
4. When the high class feels easy, the low class is the last and largest group.