Could the Mandarin word "要" (yāo) and the Thai word "เอา" (ao), both meaning "to want" be related?

Question

After a couple of weeks in Thailand and learning how to say "I don't want it" I've just realized the word for "want" is very similar to the word for "want" in Mandarin Chinese.

I know the coincidence rate is likely to be high in single syllable words but the fact the languages are so close in proximity and the large Chinese influence throughout the region still makes me wonder if it could be an old borrowing.

• Mandarin Chinese "要" (yāo)
• Thai "เอา" (ao)

It seems that the tones are quite different but I believe these tend to change more freely between dialects so I would assume even more freely when borrowing to another tonal language.

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At least going by dictionaries without much language knowledge or context there are a bunch of other words for "want" in both languages, but these are the simple ones I've been taught in each. I've looked for the Zhuang equivalent but no luck so far. I have found a Lao cognate though:

• Lao "ເອົາ" (ao)

Answer 1

You might want to check out this page http://sealang.net/thai/chinese/middle.htm which indeed claims that the word is related to 要.

เอา Prapin gloss: to want
Prapin: 606 (class 1) Chinese gloss: idem
  Karlgren: 1142a
  Big5: 要 (1) yao1 {yao4} (0) yao4 yao3 {yao1} (1) [1] [v] invite; request the presence of [2] [v] engage; date; make an agreement [3] [v] ask for; demand; claim; make a claim; request; requests [4] [v] coerce; force; blackmail; threaten [5] [v] stop [6] [v[ censure; investigate; examine [7] waist; midriff [8] a Chinese family name (0) [1] necessary; essential; necessity; important [2] must; should; ought to [3] [v] want; demand; need; require; desire; take [4] [v] summarize; [n] summary; generalization; synopsis [5] will; shall (future tense) [6] brief [7] if; in case
  GB: 要 same
  StarLing:1452 OC: ʔew MC: ʔjew Gloss: waist, waist-band
  PT/PSW เอา aw "to take (as is)"
    Brown: cited.
    Jonsson: [ *?- (A3) B101-3 ] PSW: *?aw "to take"
    Li: [ *?+əu (A1) 13.1:243 ] PSW: *?au PT: *?əu

Answer 2

Most likely, it's just a coincidence. I don't have direct proof, but here are some speculations that may (or may not) lead to an answer.

1. I think you may have been confused hearing this word with a negative particle: ไม่เอา [mâj au] which may be perceived as [mâj jau] which is used very often e.g. buying food.

2. Most Thai loanwords with Mid-Chinese origin are phonetically similar to Cantonese pronunciation, not to Mandarin Chinese. The Cantonese pronunciation of 要 is [yiu1] or [yiu3], unlike Mandarin [yau1] or [yau4].

3. There are many other words (e.g. อยาก [jàːk]) that can equally be borrowed from same Mid-Chinese word (if they were).

4. A minor difference in meanings: 要 [yau1] translates to "demand/request/important", while เอา [au] is "desire/need". In this sense, อยาก [jàːk] is more suitable for meaning of "demand" or "wish".

5. The last thing. It may or may not be relevant to เ◌า, but certainly worth thinking. When traveling to Northern Thai provinces (Chiang Mai and Chiang Rai), I found something interesting. The thing is that some diphthongs have unusual pronunciation. Here's how they read it:

   • Sara Au เ◌า [au] is read as [eaː]
   • Sara Ai Maimuan ใ◌ [ai] read as [eɯ]
   • Sara Ai Maimalai ไ◌ [ai] read as [ei]

You will probably hear examples of the last item by yourself, even in Central Thailand. For instance, people pronounce the negative particle ไม่ [mâj] as [mêj], like in:

• ไม่มี [mêj miː] "don't have" (instead of [mâj miː])
• ไม่ได้ [mêj dâːj] "can not" or "was not" (instead of [mâj dâːj])

Note that the "unofficial" pronunciation is very close to a decomposed written form, e.g. ไ = เ◌ + ◌ี, เ◌า = เ◌ + ◌า, etc.

I have also found a hypothesis expressed by Nantana Danvivathana in their book The Thai Writing System, page 188. Quoting:

Li Fan Kuei stated in his A Handbook of Comparative Tai (1977, pp. 256, 288-289) that in Lungchow, one of the Thai languages spoken in China, words written with <ไ-> in the Thai language are pronounced with [ai], while words written with <ใ-> are pronounced with [aɯ]. This gives rise to the hypothesis that in ancient Thai <ไ-> was pronounced as [ai] and <ใ-> was pronounced as [aɯ].

Note that this hypothesis does not confirm ไ◌ to [ei] or เ◌า to [eaː] phenomenon.

So if I was looking for an origin of เอา, I would rather look into words with ea pattern.

Answer 3

The usual pronunciation in Chinese is yao4 with falling tone. As Chinese and Thai are not closely related, this is probably just a chance coincidence.