Inflectional Forms

The six modern inflectional forms or 活用形かつようけい were largely developed in the Edo period through the work of Haruniwa Motoori（本居春庭）and Gimon Tōjō（東条義門）and further refined by more recenty scholars.

These inflectional forms are taught in Japanese primary schools but not in basic Western JSL curriculum. However, these are important to learn for a fuller understanding of Japanese grammar.

Modern Inflectional Forms
Inflection Form Symbol English Gloss
1 未然形みぜんけい 未 Irrealis
2 連用形れんたいよう 用 Continuative
3 終止形しゅうしけい 終 Sentence Final
4 連体形れんたいけい 体 Prenominal
5 仮定形かていけい 仮 Conditional
6 命令形めいれいけい 令 Imperative

Note: the "symbol" used above are used in some locations on this website for expediency.


Inflectional Forms, Stems & Tails

While 活用形 literally translates "conjugational tail," don't think of it as "forms," but rather loose categories or containers of stems + inflectional tails.

Here are some characteristics of inflectional forms, stems & tails that everyone needs to know:

  1. Some inflectional forms have more than one inflectional tail, depending on the the word class.
  2. Some word classes do not use all six inflectional forms, e.g. adjectives don't have an imperative form (連用形).
  3. Most inflectional tails can accept one or more (stacked) endings through the process of agglutination. These include particles, 用言 and auxiliary verbs, and nouns.
  4. Two of the inflectional forms (終止形・命令形) are self-sufficent and don't take any endings (after the inflectional tail). These types of forms are called 言い切りいいきり (lit. "statement-final") forms.
  5. Some of the inflectional forms are inherently semantic, e.g. 命令形, which always creates imperative meaning. Some forms are purely grammatic, i.e. they don't have an inherent semantic meaning, as with the 連用形.

Western textbooks typical ignore the 活用形 system because most forms are not inherently semantic. Instead these textbooks take up idiomatic phrases that have readily useable meaning – this serves to bridge to the student's first language.

For example, you probably learned 行きます as the "masu" form of the verb 行く. The JSL student immediately knows this as a polite version of "I will go." This isn't merely another form of the word 行く, but rather it's an auxiliary verb ます (which can also inflect) being attached to the 連用形 of 行く→いき.

Learning the 活用形 system is critical for having a deeper understanding for Japanese inflection and word-interaction.


A Closer Look at the Six Forms

1.　未然形 Mizenkei

The irrealis form, which describes something that hasn't happened in reality (yet). Used to make constructions such as the negative, suppositional, volitional, etc.

2.　連用形 Renyoukei

Often called the continuative form. This category usually contains an inflectional tail that is treated as the "word stem."

This form is used to attach to other inflecting words 用言ようげん, which is where the name 連用れんよう (lit. "along with inflecting words") is derived. This is generally the most productive inflectional form.

3.　終止形 Shushikei

The sentence final form. It is typically known to Westerners as the "dictionary form". It is the non-past form. This form is one of two that does not attach to any other words, i.e. an 言い切りいいきり (lit. "statement-final") form.

4.　連体形 Rentaikei

This is the pre-nominal form, used to attach to nouns. This is where the name 連体れんたい (lit. "along with nouns") is derived. 体言たいげん is used in Japanese textbooks to refer to nouns. The 連体形 is generally what Westerners consider the Dictionary form.

The difference between 連体形 and 連用形 is in the second character: 体 (lit. "body") refers to nouns, and 用 (lit. "use") to inflecting words. Just remember: inflectings words (用) are useful for changing the meaning.

The 終止形 and 連体形 verb forms look identical. The way you can tell the difference: 終止形 never attaches to other words.

The 連体形 is also called the attributive as it's used to describe nouns or make noun phrases. It is distinguished from the part of speech rentaishi 連体詞, however, which are essentially a third type of non-inflecting adjective (incidentally, these types of adjectives are most similar their English counterparts)

5.　仮定形 Kateikei

This is the conditional form in modern Japanese.

Classical Japanese had the 已然形いぜんけい instead of the 仮定形. The izenkei was more like a realis form, in contrast to the irrealis. The classical "conditional" had manefestations in both the 未然形 and 已然形.

6.　命令形 Meireikei

This is the imperative form. It does not take any additional suffixes. The 命令形 is the second of two forms that are complete in themselves. The 命令形 does not attach to any other words, it is an 言い切り form.