Japanese uses particles in order to identify elements within a sentence and to identify a sentence’s thrust or purpose. Many of these are appended to noun phrases much like a declension, to identify the phrase’s grammatical relationship to the rest of the sentence. However, Japanese does not have the common Western-style declensions identifying number and gender. Sentences are often ended with particles that either identify the sentence as interrogative, or the result of agreement with previous statements.
What I have below may not be the technical names you will find in a text book. But hopefully it will provide a quick overview of the usage of these particles.
The Topic Marker: は
Japanese can identify the topic of a sentence by appending to it the topic marker は (pronounced “wa” rather than “ha”, as the hiragana character might normally suggest). The topic marker is commonly used to identify what would be the subject in expressions that would use the English copula “to be”. Some examples:
Mr./Mrs. Sasaki is a lawyer.
りんださんは わたしの ともだちです。
rinda-san-wa watashi-no tomodachi-desu.
Linda is my friend.
The topic marker could be translated, “As for [the topic]…”. This is comparable to the use of 은/는, ŭn/nŭn, the Korean topic particle.
In addition, a noun phrase standing alone, marked only by は and pronounced with a rising intonation, is a question; it does not require the usual use of the question marker か.
The Interrogative Marker: か
with a rising intonation
A sentence ended with a rising か is easily identified as a question. No change in word order is required. Examples:
[Your] name is?
What was eaten?
with a falling intonation
With a falling tone, か ending a sentence indicates mild surprise.
A: べんごしです。 B: そうですか。
A: bengoshi-desu. B: sō-desu-ka?
A: I am a lawyer. B: Really?
The Agreement Marker: ね
Follows a statement that is expected to be agreed with, as if to say “right?”.
あれは ともだちの うちですね。
are-wa tomodachi-no uchi-desu-ne?
That (over there) is your friend’s house, right?
The Assertion Marker: よ
Call attention to information the speaker thinks the listener does not know.
I was at the airport.
The Subject Marker: が
The subject of a sentence is identified by the particle が. Answers to questions that were asked using the subject marker are also marked with the subject-marking particle. Some examples:
だれが うちに いますか。
dare-ga uchi-ni imasu-ka?
Who is at home?
Linda is [at home].
が is not directly translatable in English, but is much like a nominative ending, identifying the subject of the verb. Note here that the verb “is” in these examples is not the copula, but the verb of animate existence, 行く, いく iku.
The Object Marker: を
This particle, when it follows a noun, serves to identify the object of a verb:
I will eat sushi.
Also, the object marker helps to complete a compound verbal construction with する/します:
りんださんに でんわを します。
rinda-san-ni denwa-o shimasu.
I will telephone Linda.