When (formal) in Thai

The formal, written “when” in Thai is เมื่อmûea; in everyday speech Thais say ตอนที่dtawn-tîi.

เมื่อ mûea

when, once (formal); ago, on (a past date) conjunction

mûea falling

Falling: start high and drop clearly, like a firm “No!”

How to use it

เมื่อmûea means "when" in writing and careful speech, often with แล้วláew for "once": เมื่อถึงแล้วmûea tǔeng láew, once you arrive. Before a time in the past it means "ago" or "on": เมื่อสองปีก่อนmûea sǎwng bpii gàwn, two years ago, and the news starts with เมื่อวันที่mûea wan tîi, "on the (date)".

In conversation Thais say ตอนที่dtawn-tîi or just put the two sentences side by side. You already know เมื่อmûea from everyday words: เมื่อวานmûea-waan (yesterday) and เมื่อไหร่mûea-rài (when?).

Other spellings you'll see

There's no single official way to write Thai in English letters. We mark the tone of every syllable; online you'll also find:

meua
mua
muear

More formal words in Thai

All formal words

การ gaan Kaan (prefix)
-ing, -tion: turns a verb into a noun (the act of …)
ความ kwaam Kwaam (prefix)
-ness (turns a verb or adjective into a noun)
ผู้ pûu Phu (prefix)
person (who …): makes words for people, like -er
นัก nák Nak (prefix)
-er, -ist: someone who does it (as a job or a passion)
ซึ่ง sûeng Who, which (formal)
which, who (adds information; formal, written)
จึง jueng Therefore
so, therefore (before the verb of the result)

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Written by the Learn Thai For Free team
Audio: AI voices, quality-checked for tones