Keeping track of time ตอนที่ ๑

This is the first post of a miniseries on the etymology behind the names of the days and months in Thai (as well as the colors traditionally associated with each day). First up is the days of the week.

วันอาทิตย์ (literally "Sun day")
วันจันทร์ ("Moon day")
วันอังคาร ("Mars day")
วันพุธ ("Mercury day")
วันพฤหัสบดี ("Jupiter day")
วันศุกร์ ("Venus day")
วันเสาร์ ("Saturn day")

These match up the meanings of the weekdays' names in the Western world, too. Saturday, Sunday, and Monday are obvious, but English is a bit funky because it uses some Germanic/Norse god(esse)s:

Tuesday = Tyr's day
Wednesday = Woden's day
Thursday = Thor's day
Friday = Frige's day

Compare these to the Sanskrit weekday names:
Ravivaar
Somvaar
Mangalvaar
Budhvaar
Brihaspativaar
Shukravaar
Shanivaar

These names come from 7 of the 9 traditional celestial bodies in Hindu cosmology (known as ดาวนพเครา๊ะห์ [นบ-พะ-เคราะ] in Thai). The meanings are the same as in Thai, but they don't all use the same roots. But for those that differ we can still usually find a reflex in Thai. For example, ravi corresponds to ระวี, also meaning "sun." I can't find a source for exactly when the current Thai names were introduced, or why they differ from Sanskrit, but I do know remember from briefly studying Khmer that the days of the week nearly identical, except for the word /tŋay/ instead of วัน, so I would speculate that it comes through Khmer. You can even see the similarity in the spelling: សៅរ៍ vs. เสาร์, for example.

Another thing: Note that Sanskrit vaar corresponds with Thai วาร (or วาระ), which has a few meanings: a day, a period of time, or simply time--hence words like วารสาร "periodical" and อสมวาร [อะ-สะ-มะ-วาน] "asynchronous." However, วาร is etymologically unrelated to the Thai word วัน, or the word วาน "yesterday." (Interestingly, the native Thai word ตะวัน, also meaning "sun," most likely comes from ตาวัน, because the sun is "the eye of the day.")

Fang-Kuei Li suggests that วัน and วาน go back to the Proto-Tai *ŋwan, with the *ŋw- cluster changing to [ŋ] in some Tai languages (such as and [w] or [v] in others. (As for วาน, Li proposes it comes from *ŋwaa, and because it is a bound form--usually appearing with นี้--the word boundary was reanalyzed, under semantic influence from วัน. Thus (ง)วา นี้ became วาน นี้.) This cluster makes sense, since it would complete the set of velar clusters: kw- khw- and ŋw-.

Language = fun.