What's the origin of ～み following a 形容詞?


I found a HiNative question where someone asked about the difference between
[痛]{いた}さ and [痛]{いた}み. A native Japanese speaker gave this answer:

> 「痛さ」は形容詞「痛い」が名詞化した名詞です。
>
> 「痛み」は動詞「痛む」の連用形が名詞化した名詞です。

I was taught that み was a nominalizing suffix that is placed after
[形]{けい}[容]{よう}[詞]{し}. However, this answer seems to suggest that it is just
the [連]{れん}[用]{よう}[形]{けい} of a verb ending in ～む.

This made sense to me at first;
[痛]{いた}む、[悲]{かな}しむ、[苦]{くる}しむ、[楽]{たの}しむ、[愛]{いと}しむ →
[痛]{いた}み、[悲]{かな}しみ、[苦]{くる}しみ、[楽]{たの}しみ、[愛]{いと}しみ.

However, you then have words like nidan [温]{あたた}む, which has a
[連]{れん}[用]{よう}[形]{けい} of [温]{あたた}め, but there is an [温]{あたた}かみ, and not to
mention the extra か in there from the [形]{けい}[容]{よう}[詞]{し} [温]{あたた}かい.

So what is the deal with ～み? Where exactly does it come from? Or is it that
[痛]{いた}み is just the [連]{れん}[用]{よう}[形]{けい} of 痛む, but み in [温]{あたた}かみ is
something grammatically separate?




_" All of the み!"_

More seriously, all of the ～み here are indeed just the 連用形【れんようけい】 of the
verb-forming suffix ～む, with a base underlying meaning of "seems like, looks
like, appears like: having that quality". This ～む is very likely cognate with
suppositional and volitional verbal suffix ～む, which, via regular sound
shifts, became the modern volitional verb ending ～おう (like in 行【い】こう) or ～よう
(like in 食【た】べよう). This is also likely cognate with similar suffix ～びる (as in
words like 大人【おとな】びる, "to be or seem like an adult"; this had older form ～ぶ,
exhibiting not-uncommon //m// ↔ //b// alternation). And, this is all likely
also cognate with 見【み】る, and with 目【ま・め】.

(Consider the English cluster around _see_ and _seem_ , _look_ and _look like_
, etc.)

Note that this is looking **derivationally** , at where things come from and
how things have changed through time. My impression from various Japanese-
language materials is that most folks may well view ～み as just _" a
nominalizing suffix that is placed after [形容詞]{けいようし}"_, and they don't think
too much about how it might be related to other things.

(To be fair, most native speakers of any language don't think too much about
the language itself -- it's up to us word nerds and language geeks to do that
kind of pondering. ✨)

Regarding your observation that some verbs that end in ～む have a 連用形 of ～め～,
that's actually a slightly different derivation: あたたむ is a verb, not an
adjective + derivational suffix. あたたむ is the older form of modern あたためる. The
related adjective + derivational suffix word is instead あたたかむ, which indeed
has a 連用形 of あたたかみ.

That said, the ～む that becomes ～める in あたたむ is in turn likely cognate again
with the same ～む in あたたかむ -- but that involves a discussion of verb
conjugation paradigms that gets quite deep and involved, which would go beyond
the scope of this question. :)




_" All of the み!"_

More seriously, all of the ～み here are indeed just the 連用形【れんようけい】 of the
verb-forming suffix ～む, with a base underlying meaning of "seems like, looks
like, appears like: having that quality". This ～む is very likely cognate with
suppositional and volitional verbal suffix ～む, which, via regular sound
shifts, became the modern volitional verb ending ～おう (like in 行【い】こう) or ～よう
(like in 食【た】べよう). This is also likely cognate with similar suffix ～びる (as in
words like 大人【おとな】びる, "to be or seem like an adult"; this had older form ～ぶ,
exhibiting not-uncommon //m// ↔ //b// alternation). And, this is all likely
also cognate with 見【み】る, and with 目【ま・め】.

(Consider the English cluster around _see_ and _seem_ , _look_ and _look like_
, etc.)

Note that this is looking **derivationally** , at where things come from and
how things have changed through time. My impression from various Japanese-
language materials is that most folks may well view ～み as just _" a
nominalizing suffix that is placed after [形容詞]{けいようし}"_, and they don't think
too much about how it might be related to other things.

(To be fair, most native speakers of any language don't think too much about
the language itself -- it's up to us word nerds and language geeks to do that
kind of pondering. ✨)

Regarding your observation that some verbs that end in ～む have a 連用形 of ～め～,
that's actually a slightly different derivation: あたたむ is a verb, not an
adjective + derivational suffix. あたたむ is the older form of modern あたためる. The
related adjective + derivational suffix word is instead あたたかむ, which indeed
has a 連用形 of あたたかみ.

That said, the ～む that becomes ～める in あたたむ is in turn likely cognate again
with the same ～む in あたたかむ -- but that involves a discussion of verb
conjugation paradigms that gets quite deep and involved, which would go beyond
the scope of this question. :)

