Is あらまあ linked to Malay "alamak", and which came first?

Question

A popular theory claims that that the Japanese expression あらまあ is directly related to the Malay alamak (pronounced more or less identically, since the "k" is just a glottal stop), with speculation about which one came first and how it was imported (Malay traders in Japan, Japanese soldiers in Malaya during WW2, etc).

Is there a known etymology in Japanese, and/or evidence of use before the 1940s?

My uninformed opinion: あらまあ sounds to me like a portmanteau of あらあら and まあまあ, which are similar expressions of condolences/sympathy.

Answer 1

From the entry of 精選版日本国語大辞典:

※闇桜（1892）〈樋口一葉〉「あらマア何(どう)しませうねへ」

So the word form is attested at least since late 19th century.

As you said, this is a combination of あら + まあ. あら can be traced back to the 10th century and まあ to the 18th century with basically the same meaning as in today (interjection of amazement).

※落窪（１０Ｃ後）一「あらことごとし」

※洒落本・妓者呼子鳥（1777）四「そりゃアマアほんの事かへ」

Thus it should be natural to assume that it has developed independently from the Malay phrase, and their resemblance is a coincidence. Of course, one can argue that the either side of people learned the specific word used in the other and mimicked the phrase by a novel combination of native components, but that would be difficult to prove or disprove.

Answer 2

The "popular theory" linked from the question suggests both that the Japanese expression may have come from the Malay, or that the Malay expression may have come from from the Japanese.

The Japanese あらまあ (ara mā)

Broccoli's answer covers the Japanese. In short: あらまあ is purely Japanese, composed of purely Japanese elements and formulated in a purely Japanese word-formation pattern. Any influence from Malay is vanishingly unlikely.

The Malay alamak

For this to come from Japanese, we have to ask, "where did that final //-k// come from?"

There is no apparent mechanism for this: there is no //-k// in the Japanese, nor is there any likely longer Japanese phrase where a following word after あらまあ might start with a //k-//, since this Japanese expression is phonologically a standalone. So a borrowing appears to be ruled out purely on phonological grounds.

An internal Malay derivation may make more sense.

As described over at Wiktionary, this is probably a combination of Allah ("Allah, God") + mak ("mother"), an expression of surprise, in similar fashion to Spanish madre de Dios, Dutch moeder van God, or Arabic أُمُّ اللهِ‎ (ʾummu llāhi).