In so-called 学校文法 (the Japanese grammar which all native Japanese speakers learn at around middle school), one form of a verb is called 連用形 (aka continuative form), which looks like this (screenshot from 連用形 on Japanese Wikipedia):


As you can see, there are actually two forms of 連用形 for 五段活用 verbs (aka Group 1 verbs, consonant-stem verbs, or u-verbs). One is rather simple (changing the last -u to -i), but the other form is heavily influenced by sound changes called 音便.

Until very recently, I had believed that masu-form and te-form are the simple, straightforward terms to distinguish the two forms 連用形 listed above. I believed they are the direct subset of 連用形. 書き is the masu-form of 書く, 書い is the te-form of 書く, 立ち is the masu-form of 立つ, 立っ is the te-form of 立つ, and so on. The masu-form is called masu-form because it's typically followed by ます, and the te-form is called te-form because it's typically followed by て/で.

And finally, I realized I was wrong. If I say "te-form", listeners imagine it also includes the て/で part. I checked several free learning sites for Japanese-as-the-second-language learners and found these names (taking 読む as an example verb):

  • 読み: i-form (WP), stem (CC), verb stem (TK), 連用形 (TUFS), masu-stem, 連用形 (学校文法)
  • 読みます: i-form + masu (WP), masu-form (CC, LJA), polite form = verb stem + masu (TK), ます形 (TUFS), 連用形+助動詞"ます" (学校文法)
  • 読ん: N/A (WP, CC, LJA, TK, TUFS), 連用形 (学校文法)
  • 読んだ: perfective-form (WP), ta-form (CC, LJA), past tense (TK), た形 (TUFS), 連用形+助動詞"だ" (学校文法)
  • 読んで: te-form (WP, CC, LJA, TK), て形 (TUFS), 連用形+接続助詞"で" (学校文法)

(WP: English Wikipedia, CC: CosCom, LJA: learn-japanese-adventure.com, TK: Tae Kim's Guide to Learning Japanese, TUFS: 東京外国語大学言語モジュール)

So, what I believed was te-form is not te-form, and it doesn't even have an English name! (It can be confirmed by this question.) ます/て/で are not even considered as distinct "words" here; they are considered as a part of the conjugation of a verb. In monolingual dictionaries, ます, て/で and た/だ are all distinct words (either 助動詞 or 接続助詞) that attach 連用形.


  • Does "te-form" really only mean the form including て/で, regardless of the school/faction? If I say "読ん is the te-form of 読む" or "読み is the masu-form of 読む", am I totally wrong?
  • Is there any practical reason for not having a name for 読ん/立っ/etc and thinking of 読んだ and 読んで as different "forms"?
  • I understand that there is no single "correct grammar of Japanese", but what is the historical cause of this discrepancy? Perhaps someone was not satisfied with the Japanese grammar invented by Japanese people, and published a book with his own grammar in the past?

(PS: I'm not willing to keep using confusing terms. I just want to know the best words for learners, and, hopefully, help future native Japanese answerers who haven't heard of "te-form" or "masu-form" at all.)

  1. First we have to make a distinction between 日本語教育 and 国語教育 (which follows 学校文法). In 日本語教育 the te-form always includes the て/で part. In 国語教育 the te-form is not recognized, as it is just considered to be a perverse version of the 連用形 and not an actual newly developed form.

  2. I think there are two reasons:

    • Simplification of the grammar

      「て形」を独立した活用形の一つと考えると、「たべて」の「て」が助詞であるはずの学校文法で、 「のんで」の「で」は何なのかという、至極当然な疑問に苦しい答えを用意する必要がなくなります。 「て」を助詞だと言う必要がなく、「たべて」までで動詞なのだとすればいいからです。

    • Forms like 読んで and 読んだ can be used right away by beginner learners. They have a high usage in forms such as ~てください、てはいけません、てしまいます, etc. The 読ん/立っ only really start to make sense once you are at the intermediate level or higher

3. By introducing a new form, Japanese learners as a second language can start using the language more quickly. Native Japanese speakers already know how to speak, so this is why the approach is different.





  • 1
    Thank you, the links explain a lot, and I was so ignorant about the huge difference of 日本語教育. – naruto Jul 1 '16 at 3:02
  1. As you showed in the chart,
    • The pre-ます-form is regular 五段動詞の連用形
    • The pre-て-form is(五段動詞の連用形)+(音便)

So I think it is a correct and helpful distinction from a phrase-production perspective. Especially for learners asking questions like, "How do I say 'He is eating an apple'?"

But Japanese grammarians are likely more considered with the 音便 itself from an analytical perspective, like "Under what circumstances does 音便 happen?"

    • It might be more natural for some to think of the 五段連用形 as being forced to 音便 in the presence of words like て and た. That way you would think of 音便 as the exception rather than the rule.
    • For learners, teaching common words and phrases first (most of which use 音便) is probably less difficult and more effective than introducing the 連用形 without 音便 first. Likely because as a learner, you can quickly begin to produce new phrases by using these two separate patterns.

    • Introducing verb conjugations to Japanese 国語 learners with 「て」前置形 or 「ます」前置形 probably wouldn't pay off as much because they would already know how to produce phrases with て and ます and rather need to know the reason why certain changes seem irregular.

  • Thank you, I agree that knowing about 音便 won't help beginners at all. – naruto Jul 1 '16 at 3:14

I fear this is less an answer by itself (you have received two very good ones already), but rather a strongly related aside.

Most materials for Japanese language learners take a one-size-fits-all approach that roughly equates to "favor immediate (safe) usability (= production)". This is why nearly all common text books teach ~ます first instead of teaching the more fundamental plain form. And, this is also why you get special Japanese-for-foreign-learners grammar terms that are largely unheard of by unfamiliar native speakers.

It's nothing more than my opinion, but I feel that this has some major trade-offs (all the more so for students of an analytical nature). On one hand, it allows students to begin to play with the language, begin communicating, and grow interested in it. But on the other hand, it trades immediate usability for later misunderstanding and difficulty in using materials aimed at native Japanese speakers -- which any learner at a certain level will eventually need / want.

A more comprehensive Japanese learning program might break the learning down into two concurrent sister classes: practical and theory. The what vs. the whence. Why not take the opportunity to teach incidental grammar vocabulary as learning progresses? I find it hard to believe 動詞 is such a difficult word to teach once and use from there on out. At higher levels the theory could even move toward what native students would see in their 国語 classes: 古典、漢文、etc.

Just my 2円; hope it supplements the answers you've already been given.

  • 1
    I've always wondered why some people call 読み as "stem", and why 終止形 is called dictionary-form rather than plain-form. But they suddenly make sense to me. It's because the masu-form is the most important, basic form of a verb :) Interesting. – naruto Jul 1 '16 at 3:07
  • Somehow this reminds me of 三単現のs... – sazarando Jul 1 '16 at 3:25

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