品詞と文

1.1 Standards for identifying parts of speech

Words can be separated in various ways but one such way is through parts of speech - 品詞・ひんし. However the distinction between parts of speech is not always so clear. For example

（１）平和な世界
（２）平和の象徴

In (1) heiwa is an adjective while in (2) it is a noun. However if you line up nouns in order from concrete to abstract peace is towards the abstract, adjectival end of the spectrum. The concept of words extending over boundaries is 「品詞間の連続性・ひんしかんのれんぞくせい」 and can be seen in words such as 白 and 白い, 愛、愛する etc. Actual role can depend on context, which includes not only the words but also the situation (e.g. words at an interview may be different from those used with friends).


1.2 Parts of speech and their functions: 補語・ほご；修飾語・しゅうしょくご；述語・じゅつご　complement, modifiers and predicate

In order for a part of speech to fulfill its role, it has to be in a position in the sentence where it can exercise its role. The position can be split largely into four: 補語；連体修飾語；連用修飾語；述語。

補語　or complement, is a noun phrase with a particle attached called a 格助詞・かくじょし. Together with the 述語 the 補語 forms the main skeleton of the sentence.

The 述語 requires different 格助詞 depending on the 述語 itself. Also certain 述語 require certain 補語, called 必須補語・ひっすほご。 For example with the sentence 田中さんが乗る is missing its 必須補語, something like タクシに。

The predicate also rounds off or anchors the sentence. There are three types - 動詞、形容詞 and 判定詞 (だ、である、です etc）. Items which add on to the predicate to suplement their meaning are called 助動詞。 Sentences are can be referred to according to the type of predicate - 動詞文、形容詞文、名詞文.

There are also different types of modification - 連体修飾 is modification of nounds whereas 連用修飾 is modification of the predicate. Examples of 連用修飾 include 早く帰る、静かに話す、たいへん美しい、こう言いました。The modifier is called 修飾語 whereas the item modified is called the 被修飾語。 Adverbs, 副詞、 by default are 連用修飾. However note that some words may also function as both nouns （連体修飾） and adverbs - for example 朝はたいていパンを食べる　or たいていの場合、朝はパンである。