30430
I noticed that there is this る coming up in 日{ひ}→昼{ひる} and 夜{よ}→夜{よる}. I
haven't seen ひる and よる used a lot in Classical Japanese, so ひ and よ probably
came first.

What is the role of this る? Does it have a meaning, or is it simply a
homophone-avoiding filler like 田-んぼ and 葉-っぱ? Is it by any chance related to
雲/曇る?

* * *

# 和訳

{{pad}}
「日{ひ}→昼{ひる}」と「夜{よ}→夜{よる}」にはどちらも「る」が入っていることに気づきました。「ひる」も「よる」も文語ではあんまり見ないので、たぶん「ひ」と「よ」が元の形だと思います。

{{pad}} この「る」はどういう役割なんですか？意味があるのか、それとも「田ん **ぼ** 」や「葉っ **ぱ**
」のように、ただの同音異義語を避けるための語尾でしょうか？もしかして「雲{くも}→曇る{くもる}」の仲間ですか？
CC BY-SA 3.0
2014-07-07T12:39:09.230
17701
2016-01-18T10:21:55.840
2016-01-15T10:35:24.737
7810
2960
question
etymology
What is the etymology behind る in 日{ひ}/昼{ひる} and 夜{よ}/夜{よる}?
「る」に規則はない。しかし、最近は「る」をつけたりして、動詞のようにも使っている。外来語の場合が多い。  
例え1）トラブル(TROUBLE)という言葉は最後が「る」で、まるで動詞のように聞こえるので、「最近、彼女ととらぶっているよ」とかも使っている。  
例え2）一方、最後に「る」をつける場合は、メモ(MEMO)→「今、それメモってるの？」
CC BY-SA 3.0
2016-01-12T01:40:33.013
30369
2016-01-12T05:16:58.257
2016-01-12T05:16:58.257
9831
12189
17701
answer
I’m not a grammarian, and I cannot explain well how る in
語る、喋る、投げる、変える、帰る、照る、降る functions as the flexional form of the verb. But る of
昼（ひる）and 夜（よる）is different matter from, and irrelevant to the 語尾変化 - flexion
of the tail of Japanese verbs.

日 and 昼 are different words though their meanings look similar in English (day
and daytime, or noon), while 夜 (yo) and 夜 (yoru) are same in the meaning.

What I’m saying is I don’t find any specific meaning and reason as their own
in る in 昼 and 夜 (yoru) in terms of etymology. Perhaps it’ll be just a
coincidence.
CC BY-SA 3.0
2016-01-12T03:36:24.990
30372
2016-01-12T03:42:40.227
2016-01-12T03:42:40.227
12056
12056
17701
answer
I think that no one can give you a clear answer to the question at this time,
because all of the words, ひ, ひる, よ, and よる have existed for a very very long
time. It's just too difficult for present people to find out the origin of the
four words.

As far as I know, the words ひる, よ and よる were already common words for daily
use in the Heian period (794 - 1185). I think I can say so because
[emakimono](https://en.wikipedia.org/wiki/Emakimono) (絵巻物) written in the
Heian period contain those words, and they are used in writings which describe
their daily life or something not special. For example, all of the three words
are used in [Genji Monogatari
Emaki](https://en.wikipedia.org/wiki/Genji_Monogatari_Emaki)(源氏物語絵巻). And
other emakimono, such as Shigisan Engi Emaki
([信貴山縁起絵巻](https://ja.wikipedia.org/wiki/%E4%BF%A1%E8%B2%B4%E5%B1%B1%E7%B8%81%E8%B5%B7))
etc, contain some of them. The words were used as a word or a part of a
compound word such as ひるつかた, みじかよ etc. (Those words which I saw were written
in hiragana in the emakimono).

The word ひ meaning "daytime" (not the word ひ meaning sun, date, time or
weather here) seems to be used in [The Tale of the
Heike](https://en.wikipedia.org/wiki/The_Tale_of_the_Heike) (平家物語) and
[Kojiki](https://en.wikipedia.org/wiki/Kojiki) (古事記). (I've not seen the
reliable photos of them, so I don't know what character is actually used for
the word in them.)

All of the words ひ, ひる, よ and よる are kunyomi (訓読み). And they all were born in
the old enough time we can't (or almost can't) trace the origins now. Thus, it
is very difficult to find out which word was born first and their grammatical
compositions.

There is another Japanese word, Kami (神), which also already existed and was
used by Japanese people in the 8th century and is commonly used now. Kami is
actually very different from God, but Kami is generally translated as God in
English. Anyway, Kami has been one of very important words for many Japanese
people, maybe somewhat like the word God in English. So, not a few people have
seriously and diligently researched the origin of the word Kami for a very
long time. However, no one has succeeded in finding the perfect answer so far.
A convincing view on it still doesn't exist. So, we don't know the origin of
the Japanese word Kami etymologically. I guess that finding the origin of the
る in ひる or よる is more difficult than finding the origin of the word Kami,
because they are more ordinary words.

About which word is first, a Japanese linguist, Susumu Ōno (大野晋), wrote an
interesting thing in a book called 『日本人の神』.

>
> カミ（神）という言葉は万葉仮名では[伽未]{か・み}・[柯微]{か・み}・[可尾]{か・み}・[可味]{か・み}などと書く。ところが熟語になると形が変わって、「カム」となっている。
>
> [歌牟鵝可梨]{か・む・が・か・り}（神がかり） （神代紀上）
>
> [伽牟伽筮能]{か・む・か・ぜ・の}（神風の ＝ 伊勢にかかる[枕詞]{まくら・ことば}） （書記歌謡八）
>
> このように、カミ（神）のミはカミだけの独立語では mï 。カミを含む熟語では mu である。
>
> **こういう場合、言語学的には一般に熟語の方が古形である**
> 。例えば、こがくれ（木隠れ）、こかげ（木陰）、こがらし（木枯らし）、こだち（木立）、このは（木の葉）を、独立形のキ（木）と比較すると、キの方が新形である。

I don't know if this is true or not, but, according to his this knowledge, it
might be possible that ひる was an older word than ひ and よる was an older word
than よ if the words ひる and よる were composed of multiple words. Of course, it
can't be certain (at least for now), though.
CC BY-SA 3.0
2016-01-15T03:27:55.080
30430
2016-01-18T10:21:55.840
2020-06-17T08:18:27.500
-1
10484
17701
answer