Origin of 〜かった?


Is it by any chance the case that, historically, the い-adjective ending 〜かった
is a contraction originating from 〜くあった, where あった is the past inflection of
ある?

To me, it sure _sounds_ plausible, and would be quite elegant given how 〜く and
〜ある seem to stick together in the negative forms of い-adjectives. Is this
where 〜かった originates, or is this merely a coincidence?

**例えば**

  * 高い (?) → 高い
  * 高かった (?) → 高く **あった**
  * 高くない (?) → 高く **ない**
  * 高くなかった (?) → 高く **な** く **あった**




> Is it by any chance the case that, historically, the い-adjective ending 〜かった
> is a contraction originating from 〜くあった, where あった is the past inflection of
> ある?

That's exactly what you're seeing.

For ～い adjectives, there were three base conjugation forms:

  * ～し -- 終止形【しゅうしけい】: terminal / conclusive, for ending a sentence of clause.
  * ～き -- 連体形【れんたいけい】: attributive, for modifying a noun or other 体言【たいげん】 (uninflecting word).  
⇒ The ～し and ～き forms are fused in the modern language to just ～い.

  * ～く -- 連用形【れんようけい】: adverbial, for modifying a verb or other 用言【ようげん】 (inflecting word).

Classical grammars often also include:

  * ～けれ -- 已然形【いぜんけい】: often treated as the [realis](https://en.wikipedia.org/wiki/Realis_mood) for things that are definite, or are becoming so, or can become so; superseded in functional terms by hypothetical or conditional usage, resulting in the modern term 仮定形【かていけい】 or "hypothetical / suppositional / subjunctive form".

That said, some authors postulate that the ～けれ ending is also a fusion of ～く +
something else, often suggested as あれ. Personally, I don't see how //ku// +
//are// could possibly become //kere// just on phonetic grounds, so I wonder
if it must have been something else.

You can see a bit more about this in the conjugation table at
[https://ja.wikipedia.org/wiki/形容詞#ク活用](https://ja.wikipedia.org/wiki/%E5%BD%A2%E5%AE%B9%E8%A9%9E#%E3%82%AF%E6%B4%BB%E7%94%A8).
The so-called _-kari_ conjugation pattern clearly shows the ～く + ある fusion.




> Is it by any chance the case that, historically, the い-adjective ending 〜かった
> is a contraction originating from 〜くあった, where あった is the past inflection of
> ある?

That's exactly what you're seeing.

For ～い adjectives, there were three base conjugation forms:

  * ～し -- 終止形【しゅうしけい】: terminal / conclusive, for ending a sentence of clause.
  * ～き -- 連体形【れんたいけい】: attributive, for modifying a noun or other 体言【たいげん】 (uninflecting word).  
⇒ The ～し and ～き forms are fused in the modern language to just ～い.

  * ～く -- 連用形【れんようけい】: adverbial, for modifying a verb or other 用言【ようげん】 (inflecting word).

Classical grammars often also include:

  * ～けれ -- 已然形【いぜんけい】: often treated as the [realis](https://en.wikipedia.org/wiki/Realis_mood) for things that are definite, or are becoming so, or can become so; superseded in functional terms by hypothetical or conditional usage, resulting in the modern term 仮定形【かていけい】 or "hypothetical / suppositional / subjunctive form".

That said, some authors postulate that the ～けれ ending is also a fusion of ～く +
something else, often suggested as あれ. Personally, I don't see how //ku// +
//are// could possibly become //kere// just on phonetic grounds, so I wonder
if it must have been something else.

You can see a bit more about this in the conjugation table at
[https://ja.wikipedia.org/wiki/形容詞#ク活用](https://ja.wikipedia.org/wiki/%E5%BD%A2%E5%AE%B9%E8%A9%9E#%E3%82%AF%E6%B4%BB%E7%94%A8).
The so-called _-kari_ conjugation pattern clearly shows the ～く + ある fusion.

