Particles can be a difficult subject to master in any language. Particles subtly mark the word they follow and indicate the association between that word and the rest of the sentence. (Unlike in English, in Japanese, a particle never precedes the word it modifies. Particles always follow the modified word.) Although Japanese particles may not always have a correlation in English, they are essential to the coherency of a sentence in Japanese.
Let’s begin by looking at the most common uses of the three most common Japanese particles.
You learned a little about the particle subject marker “wa” (which is written as “ha” in hiragana) in the Sentence Structure section. At the time, you learned that “wa” marks the subject of the sentence. This is true, but it’s more common to say that “wa” marks the topic of the sentence.
Why the emphasis on topic? In Japanese, the particle “ga” can also be a subject marker, so saying that “wa” marks the topic of a sentence makes it easier to understand the difference.
The topic of a Japanese sentence is a subject that is already well known in the context. While many Japanese will omit the subject entirely should the subject be known, if they choose not to omit the subject, they will likely use the topic subject marker “wa,” which is the most frequently occurring subject marker.
Kinou imoutosan ni aimashita. Kanojo wa anata mitai desu nee.
“Yesterday I met your younger sister. She looks like you, doesn’t she…”
Notice that the subject of the first sentence, “I,” is omitted but implied. The subject of the second sentence “she” (“kanojo”) is marked with “wa” to indicate that it is a pre-referenced topic. (In the sentence before, the speaker is talking about the sister.)
Sometimes you will see a sentence with “wa” translated as “As for [topic]…” For example:
Watashi wa sono hon wo yomimashita.
“I read that book” or “As for me, I read that book.”
The latter translation implies that while the speaker read the book, others should have read it as well. (Perhaps a class of students who did not do their homework.)