Why can some words be written with or without okurigana? How do the uses differ?


What is the difference for word compounds that can exist with 送り仮名 and without
and still retain the same pronunciation?

As an example:

> 巻き貝 と 巻貝
>
> 取り引き と 取引

If I'm correct, both of these are pronounced 「まきがい」 and 「とりひき」. Do they mean
the same thing? If so, what would be a good reason for choosing one over the
other. Also, how did it come about to be this way?

The only reason I could guess that both exist is because 「取り引き」 makes the
reader pronounce it a specific way without leaving anything to question, but
please correct me if this is incorrect.




Even though they are both used, there is an official one and those that are
not.

When you consider the history of kanji incorporation into Japanese, first,
there were Chinese writings. Then, people tried to read them as Japanese. Two
techniques appeared: (i) kaeri-ten, which marks how the Chinese characters in
the original Chinese writing are to be permuted when read so that the Chinese
writing can be read as if it is Japanese, and (ii) okurigana, which marks the
inflectional endings that vary in Japanese but not in Chinese.

Hence, the purpose of okurigana is to mark the varied part of a word. This
works for verbs. Now, once a verb is turned into a noun, and starts to be
recognized as a noun that is independent of the original verb, there is no
more purpose to keep the okurigana. That is where the reduction of okurigana
happens.

Variation among the okurigana reflects the fact that it is not clear when a
deverbal noun is created: some people might feel a word is still an inflected
form of a verb whereas other people may feel that the word has evolved into an
independent noun and has lost connection to the original verb. There is an
[official web page
送り仮名の付け方](https://www.bunka.go.jp/kokugo_nihongo/sisaku/joho/joho/kijun/naikaku/okurikana/index.html),
but people have varied perception.




Even though they are both used, there is an official one and those that are
not.

When you consider the history of kanji incorporation into Japanese, first,
there were Chinese writings. Then, people tried to read them as Japanese. Two
techniques appeared: (i) kaeri-ten, which marks how the Chinese characters in
the original Chinese writing are to be permuted when read so that the Chinese
writing can be read as if it is Japanese, and (ii) okurigana, which marks the
inflectional endings that vary in Japanese but not in Chinese.

Hence, the purpose of okurigana is to mark the varied part of a word. This
works for verbs. Now, once a verb is turned into a noun, and starts to be
recognized as a noun that is independent of the original verb, there is no
more purpose to keep the okurigana. That is where the reduction of okurigana
happens.

Variation among the okurigana reflects the fact that it is not clear when a
deverbal noun is created: some people might feel a word is still an inflected
form of a verb whereas other people may feel that the word has evolved into an
independent noun and has lost connection to the original verb. There is an
[official web page
送り仮名の付け方](https://www.bunka.go.jp/kokugo_nihongo/sisaku/joho/joho/kijun/naikaku/okurikana/index.html),
but people have varied perception.

