A sentence has multiple words. There is some relation between words.

He ate an apple.

A relation included in this sentence can be illustrated as below.

This relation can be abstracted as below.

We can abstract it further, such as;

Consider “case” as a box contains grammatical elements.
A sentence has several cases and a relation(relations) between them.
Each “case” has its own role (e.g. Subject, object, etc.) in a relation.

This conceptual image is common in many languages. Figure 2 and 3 seems very similar, but contrary to figure 2 which shows English grammar, figure 3 shows a language independent conceptual model.

 

Understanding a sentence is an activity of mapping words in a sentence to a conceptual model.

Each language has its own mapping system. There are many differences between the mapping systems of English and Japanese.

Basically, the words-model mapping system in English is “word order based”. A word before a verb takes a role of subject, and after is an object.

In contrast, the system in Japanese is “case particle based mapping”.

The grammatical function of “が” and “を” in the above figure is generally called “case particle(格助詞,かくじょし in Japanese)”.
Particles are grammatical elements placed after some word. Case particle is a kind of them, indicates a case:role of a word in a sentence.

“が” is a case particle and its major function is subject marking.
“が” indicates that the word before it is the subject.
(There are some different usage patterns that “が” doesn’t indicate subjects, discussed in later posts)

“を” is also a case particle, and it indicates that the word before it is the object.

In Japanese there are a variety of such case particles which indicate different roles in a sentence.

Do you understand so far?

1. Each language has its own word-model mapping system.
2. Those of English and Japanese are fundamentally different.
3. Japanese language uses “case particles based mapping”.
4. Case particle “が” is a subject marker, indicates a subject.

Is it okay?

However, “が” in the following sentences don’t meet the 4th item above.

コーヒーが飲みたい。 I want to drink a cup of coffee.
音楽が好きです。 I like music.
英語が話せます。 I can speak English.

Let’s study about it in the next post.