If you are curious why the te form conjugates strangely or you have problems understanding it then this post is for you ;>
To understand て form we have to go back in the past to see how it all started, and why modern Japanese learners have to memorize its conjugations.
It all started in classical Japanese with an auxiliary verb つ (auxiliary forms, unlike normal verbs, are dependant, that is they cannot function by themselves and are added to various conjugations of verbs and adjectives).
つ originally expressed completion of the action (like た and ました in modern japanese), certainty (like 確かに in modern japanese), and affirmation. Later it also expressed the meaning of parallel actions in つ〜つ construction, which is alive even today).
| 未然形（imperfective form (things that not happened), nai stem) | て |
|---|---|
| 連用形(conjunctive form (connects), masu stem) | て |
| 終止形(predicative form, ending form) | つ |
| 連体形(attributive form, noun modifying form) | つる |
| 已然形(realis form (thing that happened, used with ば and ども as in けれども) | つれ |
| 命令形(imperative form) used for orders | てよ |
In this table, we can see some very, very familiar forms.
The modern て form originates from the 連用形 (check a table below to see how it looks like) of the つ form.
The 連用形 (conjunctive form, continuative form, masu-stem, or formal conjunctive) is the form of a verb that indicates simultaneous or sequential action. Auxiliary verbs that express something completing were attached to 連用形 and つ was one of them. Combination of the complete meaning and simultaneous/sequential action meaning gave us one of the て form functions.
(I think many might find it interesting that 連用形 also works like a nominalizer, for example
When it is followed by particle に (に行く), similarly 連用形 of adjectives also allows them to function as nouns, that’s why particle は can follow 連用形 of adjectives, and why 多く is considered a noun as in 多くの) since て form is 連用形 of つ, therefore, it also has some of this properties, that’s why we can sometimes see において followed by particles like の、は、も for example においての、にしては、にしても）. This usage gave birth to many modern, independent nouns.
たくさんお腹（なか）が痛（いた）いよ。
連用形 also can modify verbs and all inflected forms that follow it, in other words, it works as an adverb.
| Verb | 連用形 (masu stem) | 連用形 + て |
|---|---|---|
| 見（み）る | 見 | 見て |
| 座（すわ）る | 座り | 座りて |
| 打（う）つ | 打ち | 打ちて |
| 歩（ある）く | 歩き | 歩きて |
| 泳（およ）ぐ | 泳ぎ | 泳ぎて |
| 死（し）ぬ | 死に | 死にて |
| 飛（と）ぶ | 飛び | 飛びて |
| 休(やす）む | 休み | 休みて |
| 話(はな）す | 話し | 話して |
(To make it simple, I used modern forms of verbs)
Then the sound changes happened, because people simplified pronunciation, to talk easier and faster.
The first sound change was the I sound change the same I mentioned in the previous post about history of i adjectives . The き and ぎ conjugations changed to just い.
| Verb | Old conjugation | New conjugation |
|---|---|---|
| 歩く | 歩きて | 歩いて |
| 泳ぐ | 泳ぎで | 泳いで |
Then the nasalized sound change (try saying Nnnn, the air flows through your nose and mouth at the same time) happened and び、み、に became nasal ん and were followed by a voiced version of the following article (in other words で for te form, だり for たり and so on)
| Verb | Old conjugation | New conjugation |
|---|---|---|
| 飛ぶ | 飛びて | 飛んで |
| 休む | 休みて | 休んで |
| 死ぬ | 死にて | 死んで |
And then ち、ひ and り changed to つ (which in Heian period changed to small っ making pronunciation even easier).
| Verb | Old conjugation | New conjugation |
|---|---|---|
| 打つ | 打ちて | 打つて→打って |
| 座る | 座り | 座つて→座って |
As you probably noticed, I have omitted modern verbs ending with う. There is a reason.
Well, they didn’t exist back then, as they are the product of voice changes themselves and had more complicated conjugations.
| Verb | At the time | 連用 + て |
|---|---|---|
| 思（おも）う | 思（おも）ふ | 思ひて(ふ changed into ひ) |
I won’t go into details about why ふ changes to ひ, since it’s for another article, but it has a lot to do with why we pronounce は as wa.
As I mentioned above, ひ changed to つ so we get the modern form.
| Verb | Old conjugation | New conjugation |
|---|---|---|
| 思（おも）ふ | 思ひて(ふ changed into ひ) | 思つて→思って |
And this is why te form has seemingly illogical conjugations, but you know it now. :>
As for the functions of modern て form (which evolved from the classical functions):
Action completed after another action:
食（た）べて寝（ね）た。
I ate and went to sleep. (That’s why happened 1 hour ago)
- Simultaneous actions or states.
雨（あめ）が降（ふ）って雷（かみなり）が鳴（な）る。
It rains and thunders.
猫（ねこ）は太（ふ）っていて、小（ちい）さい。
The cat is fat and small.
Notice that states are expressed by adjectives and intransitive verbs.
- Contrast (Similar to が - but)
私（わたし）は買（か）い物（もの）に行（い）って妹（いもうと）は映画館（えいがかん）に行（い）った。
I went shopping and (or but) my younger sister went to the cinema.
Notice that actions are done by different people marked by は (which expressed contrast). This is a special case of simultaneous actions.
- Means and manners (an action that is used to achieve a certain result)
フライパンを使（つか）って、料理（りょうり）をします。
I am making a meal with a frying pan.
- Reason and cause
たくさん食（た）べてお腹（なか）が痛（いた）いよ。
I have an upset stomach because I ate a lot.
I ate a lot and I have an upset stomach.
コーラを飲（の）んで寝（ね）られない。
I cannot sleep because I’ve drunk coke.
I’ve drunk coke and (so) I cannot sleep.
It expresses the reason/cause only when て is followed by verbs in potential form, and words expressing feelings て困（こま）る、て嬉（うれ）しい、て大変（たいへん）、てびっくり、て疲（つか）れている、て心配（しんぱい）、て休（やす）む、て安心（あんしん）、て◯が痛（いた）い、て気持（きも）ちがいい).
- Convey request (special use of the 5, where ください or other word is omitted)
助けて（ください｜よ）！
(PLEASE) HELP ME!
- Expressing condition with は：
寝（ね）る前（まえ）にコカ・コーラを飲（の）んでは寝（ね）られない。
If you drink cola before going to bed, you won’t be able to sleep.
Usually what follows ては is a negative consequence.
てはいけない is a case of this:
使ってはいけない。You must not use it.
- ては ては repeating action (this comes from つ〜つ mentioned at the beginning）
働（はたら）いては寝（ね）て、働（はたら）いては寝（ね）てばかりだ。
I only work and sleep, work and sleep.
- In all kinds of expressions, followed by ください てもいい and so on.
Notice that many of those meanings are deduced from context like following verbs, rather than て form itself and without that extra knowledge, it might be simply translated as “and”. Therefore knowing those we can understand the language and its nuances better.
I am mrnoone, and that was all about the てform.