Exceptional compounding forms


There are a number of Japanese words which have distinct compounding forms:

  * -a/-e alternation: 天・雨、酒、上、風、目 — many examples.
  * -u/-i alternation: 神（[神]{かむ}[集]{つど}ふ）、月（[月]{つく}[読]{よみ}）
  * -o/-i alternation: 木（[木]{こ}の[葉]{は}）、火（炎【ほのほ】）
  * -a/-o alternation: 白（[白]{しら}[雪]{ゆき}）

[This BBS
post](http://jbbs.livedoor.jp/bbs/read.cgi/study/10958/1283085223/18) has more
examples. There is also another kind of alternation I know of, even rarer:

  * s-insertion: 雨（[春]{はる}[雨]{さめ}）、青（[真]{ま}っ[青]{さを})

I have three questions:

  1. Are there any other alternations I have missed?
  2. Is there an exhaustive listing of words with exceptional compound forms somewhere?
  3. To what extent is this process still alive? For instance, [風]{かざ}[車]{ぐるま} is a comparatively recent coinage.




As I commented earlier, I am pretty sure that much of these alternations are
due to phonological rules. I realized that, among your patterns,
a/e-alternation and u/i-alternation follow naturally from assuming:

  1. 露出形 vs. 被覆形 alternation hypothesis (which you also mention) as in my answer in [Why is a place that sells さけ a さかや?](https://japanese.stackexchange.com/questions/3533)
  2. The phonological rule described in my answer in [What does こまけー mean?](https://japanese.stackexchange.com/questions/3746)
  3. The long vowel mentioned in 2. above was shortened.

However, this does not explain your o/i-alternation and a/o-alternation. This
fact suggest two possibilities: (1) the underlying verb is of somewhat
different quality, and assuming an appropriate underlying vowel, these
alternation actually fit the rule mentioned in 2, or (2) there is another rule
in addition to the one mentioned in (2).

To the extent that this theory is correct, it predicts that there can be
o/e-alternation such that in compound forms, ends with [o], and in isolated
forms, ends with [e].

