Thai romanization explained: khrueng, kreung or krueng?

Thai has 44 consonants, long and short vowels, and five tones. English letters have none of the tools to show most of that, so everyone who writes Thai in Latin letters has to make choices. Different choices give different spellings, and that’s why your cousin writes kreung, your passport office writes khrueng and a menu writes krueng.

Why Thai doesn’t fit English letters

Three things cause most of the variation:

• Breathy and plain consonants. Thai separates k from kh (a k with a puff of air), p from ph and t from th. In English those are the same letters, so writers add an h, or don’t. That ph is never an f, and th is never the th in the.
• Vowels English doesn’t have. The vowel in ครึ่ง is like oo said with spread lips. RTGS writes it ue; others write eu, u or ua.
• Length and tone. ยาย (grandma) and ใหญ่ (big) differ in vowel length and tone. Most systems write both as yai.

RTGS: the official system

The Royal Thai General System of Transcription is the Royal Institute’s system (the institute is now the Royal Society of Thailand), announced in its current form in the Royal Gazette in 1999. It is what you see on road signs and in government publications, though even official use is inconsistent.

Its rules, in short:

• Plain Latin letters only: no accents and no tone marks.
• ph, th, kh are the breathy consonants; p, t, k the plain ones. Both จ and ช are ch.
• No vowel length: ยาย and ใหญ่ are both yai; ข้าว (rice) and เข้า (enter) are both khao.
• Final consonants are written as they sound, not as they’re spelled: วัด is wat.
• Words are separated by spaces; compounds and personal names are written as one word.

Everyday spellings

Outside the official system, Thai gets written however looks right to the writer: sawasdee for สวัสดี (RTGS sawatdi), kob kun for ขอบคุณ (RTGS khop khun), look kreung for ลูกครึ่ง. Restaurant menus, brand names, Thai pop stars and the family group chat all do this. Some of it follows the Thai letters instead of the sound, which is why สวัสดี ends up with an s in it.

None of these is wrong. They are just not a system, so the same word can come out differently each time.

The family-friendly style in our app

The Reply Thai app uses its own scheme, made for people who already half-know the words by ear. It starts from RTGS and changes the parts that trip up English and Swedish readers:

Like RTGS, the app writes no tone marks: the Thai script and the audio carry the tone. The trade-off is honest. Our spelling helps you say the word, RTGS helps you recognise official names, and neither replaces the script.

กินข้าวหรือยัง

gin khaao rue yang

Draft: waiting for a native speaker’s review.

Practise replying to this in Reply Thai, coming soon to iPhone.

Your own name

If your Thai name is on your passport, that spelling is your name in Latin letters, whatever system it follows. Don’t “correct” it to RTGS; institutions match documents letter for letter. For anything new, like a nickname on a family tree, pick one system and use it every time.

Turn Thai script into letters yourself

Paste any Thai into our karaoke Thai romanizer and choose RTGS or the family-friendly style. It runs in your browser and marks the words it had to guess. If you’d rather read the script itself, start with the Thai alphabet for heritage learners. To type Thai yourself, see the Thai keyboard guide.

Thai words on this page are a draft until a native speaker has reviewed them.