Why is the Japanese word for Brunei ブルネイ and not ブルナイ?


The English pronunciation of Brunei is /bɹuːˈnaɪ/ and the Brunei Malay
pronunciation ends in something like /ai/, as far as I can tell (I'm not
totally sure about this, but here's the
[Sultan](https://youtu.be/eIRZUInNHxI?t=285) and the [Second Minister of
Foreign Affairs and Trade](https://youtu.be/WAi2RRWuujg?t=140) saying it that
way - although they're speaking in English - and this news reader clearly says
it [here](https://www.youtube.com/watch?v=DSrN0wP3UnQ)), yet in Japanese the
country's (short) name is ブルネイ, not ブルナイ.

Wikipedia
[lists](https://ja.wikipedia.org/wiki/%E5%9B%BD%E5%90%8D%E3%81%AE%E6%BC%A2%E5%AD%97%E8%A1%A8%E8%A8%98%E4%B8%80%E8%A6%A7)
4 ways of writing the country's name in 漢字 that all end with /ai/:

  * 文莱 (ブンライ?)
  * 文萊 (ブンライ?)
  * 芠萊 (ブンライ?)
  * 婆羅乃 (バラナイ?)

and the Simplified Chinese 文莱 (wénlái) and Traditional Chinese 汶萊 (wènlái). In
Korean it's 브루나이 (beurunai).

Given all this, how did Japanese end up using ブルネイ?




I'm no expert on Malay. That said, if [this Wikipedia
article](https://en.wikipedia.org/wiki/Malay_phonology#Diphthongs) is anything
to go by, it appears that the ⟨ei⟩ combination in Malay spellings in general
is pronounced as //ei//, in line with the Japanese katakana rendering of ブルネイ.
Checking the spellings of the country's name in the different languages
available on Wikipedia, I see that most use the same _Brunei_ spelling,
rendered in the local phonology as something approaching either //brunei//
(such as for [Spanish](https://es.wikipedia.org/wiki/Brun%C3%A9i),
[Hawaiian](https://haw.wikipedia.org/wiki/Brunei),
[Welsh](https://cy.wikipedia.org/wiki/Brwnei), or
[Russian](https://ru.wikipedia.org/wiki/%D0%91%D1%80%D1%83%D0%BD%D0%B5%D0%B9))
or //brunai// (such as for [German](https://de.wikipedia.org/wiki/Brunei),
[English](https://en.wikipedia.org/wiki/Brunei), or
[Danish](https://da.wikipedia.org/wiki/Brunei)).

A close reading of (the Wikipedia article on [Malay
phonology](https://en.wikipedia.org/wiki/Malay_phonology) shows that ⟨e⟩ is
occasionally realized as //ə// (the schwa sound), which might account for the
variance. Alternatively, the variance might reflect different transmission
routes for how the term was borrowed, and influence from the native
orthographies and phonologies of the borrowing languages.

For the Japanese term in specific, I cannot find any source that definitively
states the source language. The notation used in Shogakukan's monolingual
国語大辞典 matches that used in [the Daijirin
entry](https://kotobank.jp/word/%E3%83%96%E3%83%AB%E3%83%8D%E3%82%A4-127375#E5.A4.A7.E8.BE.9E.E6.9E.97.20.E7.AC.AC.E4.B8.89.E7.89.88),
where the etymon (source term) is listed simply as **【Brunei】** with no source
language given. We can probably safely interpret this to suggest that the
katakana rendering is based on the spelling.




I'm no expert on Malay. That said, if [this Wikipedia
article](https://en.wikipedia.org/wiki/Malay_phonology#Diphthongs) is anything
to go by, it appears that the ⟨ei⟩ combination in Malay spellings in general
is pronounced as //ei//, in line with the Japanese katakana rendering of ブルネイ.
Checking the spellings of the country's name in the different languages
available on Wikipedia, I see that most use the same _Brunei_ spelling,
rendered in the local phonology as something approaching either //brunei//
(such as for [Spanish](https://es.wikipedia.org/wiki/Brun%C3%A9i),
[Hawaiian](https://haw.wikipedia.org/wiki/Brunei),
[Welsh](https://cy.wikipedia.org/wiki/Brwnei), or
[Russian](https://ru.wikipedia.org/wiki/%D0%91%D1%80%D1%83%D0%BD%D0%B5%D0%B9))
or //brunai// (such as for [German](https://de.wikipedia.org/wiki/Brunei),
[English](https://en.wikipedia.org/wiki/Brunei), or
[Danish](https://da.wikipedia.org/wiki/Brunei)).

A close reading of (the Wikipedia article on [Malay
phonology](https://en.wikipedia.org/wiki/Malay_phonology) shows that ⟨e⟩ is
occasionally realized as //ə// (the schwa sound), which might account for the
variance. Alternatively, the variance might reflect different transmission
routes for how the term was borrowed, and influence from the native
orthographies and phonologies of the borrowing languages.

For the Japanese term in specific, I cannot find any source that definitively
states the source language. The notation used in Shogakukan's monolingual
国語大辞典 matches that used in [the Daijirin
entry](https://kotobank.jp/word/%E3%83%96%E3%83%AB%E3%83%8D%E3%82%A4-127375#E5.A4.A7.E8.BE.9E.E6.9E.97.20.E7.AC.AC.E4.B8.89.E7.89.88),
where the etymon (source term) is listed simply as **【Brunei】** with no source
language given. We can probably safely interpret this to suggest that the
katakana rendering is based on the spelling.

