Pad, phat or phad? Why Thai menus spell dishes differently, and the RTGS
Thailand's official RTGS spells ผัด as phat, yet most menus say pad. A study of 15 Thai menus in Paris found they did not follow it. How to read menus right.
- Pad, phat and phad are the same word, ผัด (stir-fried); only the romanization differs.
- The official RTGS leaves out tones and vowel length and uses ph, th and kh for breathy (aspirated) sounds.
- A study of 15 Thai restaurant menus in Paris found their spellings did not follow RTGS and varied more than formal translations.
- To be sure of a dish abroad, look at the Thai name or ask what is in it; do not guess from the spelling.
Pad, phat and phad on a menu are the same word: ผัด, stir-fried. The only difference is how the writer turned Thai sounds into Latin letters. Thailand has an official system, the RTGS, which spells it phat, but restaurants rarely use it. A Mahasarakham University study of 15 Thai restaurant menus in Paris found that their spellings did not follow the official system.
Knowing the logic makes English menus easier to read, and lets you explain to friends why one dish can be spelled several ways.
What RTGS is
The RTGS (Royal Thai General System of Transcription) is the Royal Institute of Thailand’s system for writing Thai sounds in Latin letters. The current version dates from 1999. It is used on road signs and in government publications, though Wikipedia notes that even government use is inconsistent.
Five key rules:
- Write the sound, not the Thai spelling. A final ด or บ is written t or p.
- No tone marks.
- No vowel length. Short and long a are both a.
- An h marks a breathy sound. Ph, th and kh are พ, ท and ค; p, t and k are ป, ต and ก.
- Some vowels have their own spelling. อึ/อือ is ue, and เอือ is uea.
| Thai letter | Start of syllable | End of syllable |
|---|---|---|
| ป | p | p |
| พ ผ ภ | ph | p |
| ต | t | t |
| ท | th | t |
| ก | k | k |
| ค ข | kh | k |
| จ | ch | t |
| ช | ch | t |
| ด | d | t |
| บ | b | p |
Criticisms of RTGS: it shows no tones, no vowel length, uses ch for both จ and ช, and o for two different vowels.
Worked example: ผัดกะเพราหมูสับ, syllable by syllable
- ผัด: ผ at the start = ph, short a = a, final ด = t, giving phat
- กะ: ก = k, short a = a, giving ka
- เพรา: พร = phr, เ-า = ao, giving phrao; joined with the syllable before, kaphrao
- หมู: ม = m, long u written u, giving mu
- สับ: ส = s, short a = a, final บ = p, giving sap
The RTGS result is phat kaphrao mu sap (stir-fried holy basil with minced pork). Menus often say something like “pad kra pao moo”. Different spelling, same plate.
How menus actually spell it
| Thai | RTGS | Other spellings you may see |
|---|---|---|
| ผัดไทย | phat thai | pad thai, phad thai |
| ผัดกะเพรา | phat kaphrao | pad kra pao, pad kaprao |
| ต้มยำกุ้ง | tom yam kung | tom yum goong |
| ข้าวผัด | khao phat | khao pad |
| ไข่ดาว | khai dao | kai dao |
| เผ็ด | phet | phed, pet |
Wikipedia’s own article is titled “Pad thai”, gives the RTGS as phat thai, and lists Phad thai and Phat thai as alternative names.
The study of 15 menus in Paris
A Mahasarakham University study, published in the Journal of Language and Linguistics in 2022, collected bilingual menus from 15 Thai restaurants in Paris with Thai owners or staff, and compared them with four Thai novels translated into French. Findings worth knowing:
- The spellings did not follow RTGS. The researcher found four approaches: letter-by-letter transliteration, sound-based transcription, English-style spelling and French-style spelling.
- พ, ผ, ภ at the start of a word were written p 67.82% of the time on menus and ph (the RTGS form) only 32.18%. In French, ph always reads as f, so menus avoid it.
- A final t sound was written d on menus 70% of the time, and every such word was spelled with ด in Thai, such as ped for เป็ด (duck). The translated novels used t, as RTGS does, every time.
- จ was written j 76.93% of the time on menus; ช was written ch 97.22% of the time.
- Formal writing was more consistent. Menus varied far more than the translated literature.
One caution: this study looked at menus in France, so the percentages do not transfer directly to English menus. The overall picture is the same, though: menus spell by ear and by the Thai letters more than by the official system.
Different spelling on a menu does not mean a different dish. Check the Thai name or ask about the ingredients first.
Common mistakes
- Reading ph as f. Phat does not sound like “fat”; ph is a p with a puff of air.
- Reading th as in “think”. The th in Thai is a t with a puff of air, not the English th sound.
- Thinking pad and phat are different dishes. They are the same word.
- Guessing from khao alone. Rice, white, enter and he are all khao in RTGS.
- Calling a menu “wrong”. RTGS is the government standard; a menu that spells differently just is not following it. A menu’s job is to be readable.
Summary
Pad, phat and phad are all ผัด. RTGS writes phat because it follows sound: ผ = ph and a final ด = t. Most restaurants spell by ear instead, and a study of 15 menus in Paris found they did not follow the official system. When ordering abroad, check the Thai name or ask about the ingredients rather than guessing from the spelling. For how to order the popular one-plate dishes, see one-plate meals.
Sources
FAQ
Which is right, pad thai or phat thai?
The official RTGS spelling is phat thai, but the name most people know, and most menus use, is pad thai. Both mean the same dish, ผัดไทย.
Why is the ph in Thai words not an f sound?
In RTGS, an h after p, t or k marks a breathy (aspirated) sound. Ph is the Thai พ, ผ or ภ, a p with a puff of air, not the f in phone.
Why can khao mean several things?
RTGS writes no tones and no vowel length, so ข้าว (rice), ขาว (white), เข้า (enter) and เขา (he) are all khao. Context or the Thai script tells them apart.
Ingredients and heat vary by kitchen and recipe. If you have a food allergy, ask before you order, every time.