What is the meaning and application of ren'youkei?


My knowledge about ren'youkei is limited to "tabe is the ren'youkei of
taberu". I would like to know what the meaning of ren'youkei is, what
linguistic idea lies behind this term and for what it is actually used in
everyday usage.




The 連用形{れんようけい} ("continuative form") is one of the various 活用形｛かつようけい}
("inflected forms") for 用言{ようげん} ("inflectable words") in Japanese.

The way I like to explain this is somewhat non-standard, but I think more
coherent than how it is usually explained. I will connect this explanation
back to the standard way at the end.

* * *

I think there are two things worth discussing:

  1. The `-I` Form
  2. The Continuative Form

# The `-I` Form

The `-I` form is `stem-I`: the stem of an inflectable word plus the -I
morpheme.

**`-I` definition:**

  * Vowel-stem verb: `∅`
  * Consonant-stem verb: `i`
  * i-adjective: `∅`

**Examples:**

  * Consonant-stem verb 思う: `omow-I -> omo(w)-i -> 思い`
  * Consonant-stem verb 行く: `ik-I -> ik-i -> 行き`
  * i-adjective 熱い: `atsu-I -> atsu-∅ -> 熱`
  * Vowel-stem verb 食べる: `tabe-I -> tabe-∅ -> 食べ`

The `-I` form feels a lot like a noun.

**Uses:**

  * The continuative form 
    * See later for examples.
  * -sou and -sugi- 
    * **熱** そう
    * **行き** そう
    * **熱** すぎる
    * **食べ** すぎる
  * Compounding 
    * **早** 起き
  * Stand-alone nouns (I can only think of verbs here) 
    * **思い**
    * **考え**
    * **感じ**

# The Continuative Form

The continuative form (a.k.a., 連用形) is `stem-I-CONT`: the stem of an
inflectable word, plus the `-I` morpheme, plus the `-CONT` morpheme.

**`-CONT` definition:**

  * Verbs: `∅`
  * i-adjectives: `ku`

**Examples:**

  * Consonant-stem verb 思う: `omow-I-CONT -> omo(w)-i-∅ -> 思い`
  * Consonant-stem verb 行く: `ik-I-CONT -> ik-i-∅ -> 行き`
  * i-adjective 熱い: `atsu-I-CONT -> atsu-∅-ku -> 熱く`
  * Vowel-stem verb 食べる: `tabe-I-CONT -> tabe-∅-∅ -> 食べ`

**Uses:**

  * Adjuncts:  

    * **間違いなく** 怒っている。
    * **優しく** 抱きしめる。
    * 君のことを **思い** 、彼を許した。
  * Conjunction (this form is known as the 中止形): 
    * 外へ **行き** 、マスコミに話す。
    * 空は **青く** 、地面は茶色。
  * -te: 
    * **熱く** て
    * **食べ** て
    * **思っ** て (omo(w)-i-te after euphonic changes, namely 促音便)
  * Various auxiliaries, e.g.: 
    * -mas-: **行き** ます
    * -tutu-: **直り** つつ

* * *

While this is hardly complete, maybe it helps give an idea of what the 連用形 is.
The way this stuff is usually taught, I think the -i form is often conflated
with the 連用形, because the surface form is the same for verbs, but I think it
makes more sense to split it out like this.

