readings of north, south, east, west?

Question

This sentence appeared here:

https://www.asahi.com/articles/DA3S15638672.html?iref=comtop_Opinion_05

日本語【にほんご】では東西南北【とうざいなんぼく】だが、中国語【ちゅうごくご】では東南西北【とうなんせいほく】と書【か】く。一方【いっぽう】で、英語【えいご】では北南東西【きたなんとうにし】の順【じゅん】になることが多【おお】い。

In Japanese it's east, west, south, north and south, but in Chinese it's written east, south, west and north. In English, on the other hand, the order is often north, south, east, and west.

1. Are the computer-generated furigana correct?
2. If the furigana are correct, why do the kanji have different readings?

Answer 1

とうざいなんぼく is the correct reading of those characters when they are put together in that order.

The second one being Chinese, it is natural to read it in all on’yomi. Besides, 東南 and 西北 are both existing words in Japanese and they are read とうなん and せいほく, respectively. No one would think it’s strange. (In a mahjong context, it would be read トンナンシャーペイ. I don’t know why 西 is シャー, not シー.)

The last one is not a valid compound in Japanese. It’s just a list of directions, It could have as well been written 北、南、東、西. The auto-generated furigana picked the first valid compound 南東 and gave it the right reading. It should be read in either all on’yomi or all kun’yomi.

Answer 2

In such compounds, I would rather expect that on'yomi would be used, not kun'yomi.

西 has 2 widely used on'yomi readings: さい and せい.

東西南北 happens to be pre-existing Sino-Japanese word, included in dictionaries, with reading とうざいなんぼく. Voicing of /s/ to /z/ in ざい is result of rendaku. It happens sometimes, but not always, in compound words. Change of /h/ to /b/ in ぼく is also caused by rendaku. Modern Japanese consonants /ɸ/, /h/, /ç/ come from Old Japanese consonant /p/.

Japanese reading generated for Chinese word 東南西北 (in Modern Mandarin: Pinyin romanization: dōngnánxīběi, /tʊŋ⁵⁵ nän³⁵⁻⁵⁵ ɕi⁵⁵ peɪ̯²¹⁴⁻²¹⁽⁴⁾/) at least consists of valid on'yomi of these kanji. (せい reading was guessed here for 西.)

Japanese reading generated for 北南東西 consists of kun'yomi for 北, on'yomi for 南 and 東, and kun'yomi for 西. This does not seem correct.