Particles は / が and Polite です

You’ll be able to

Use は (wa) to mark the topic and です to make a polite statement
Distinguish the topic particle は from the subject particle が
Introduce family members politely

The topic marker は and です

Japanese sentences often start by naming a topic with the particle は (written は but pronounced wa as a particle). The basic frame is [topic] は [comment] です: 私は学生です (Watashi wa gakusei desu, “I am a student”). Here です (desu) is the polite copula, roughly “to be,” placed at the very end. Word order is topic first, verb last. To introduce family: これは母です (Kore wa haha desu, “This is my mother”).

は versus が

Both は and が can mark what English calls the subject, but they differ. は sets the topic — the known thing we are commenting on, often translatable as “as for …”: 父は先生です (Chichi wa sensei desu, “[As for] my father, he is a teacher”). が marks the subject and tends to introduce new information or answer “who/what?”: 誰が来ますか (Dare ga kimasu ka, “Who is coming?”) → 母が来ます (Haha ga kimasu, “My mother is coming”). Use が when spotlighting the identity; use は for the established topic.

Humble words for your own family

Japanese has two sets of family terms: humble ones for your own family, and polite ones for someone else’s. Your own: 父 (chichi, “my father”), 母 (haha, “my mother”), 兄 (ani, “my older brother”). Someone else’s (add お/ご and honorific suffixes): お父さん (otōsan, “your/his father”), お母さん (okāsan), お兄さん (onīsan). Saying 私の母は… (Watashi no haha wa…, “my mother …”) but お母さんは… when asking about the listener’s mother is an essential politeness distinction.

Worked example

Answer the question 誰が日本語を話しますか (Dare ga Nihongo o hanashimasu ka, “Who speaks Japanese?”) with “My mother speaks it,” then restate it as a general topic sentence about your mother. Explain the は/が choice.

1.The question asks specifically “who?”, so the answer highlights new-information identity — use が: 母が話します (Haha ga hanashimasu, “My mother speaks [it]”).
2.Because the question already established the action, the focus is the doer, which is exactly what が marks.
3.Now make a general statement taking the mother as the known topic: 母は日本語を話します (Haha wa Nihongo o hanashimasu).
4.Here は presents 母 as the topic (“as for my mother …”), not as brand-new information.

Answer: Answering “who?”: 母が話します (Haha ga hanashimasu) — が spotlights the mother as the new-information subject. As a topic statement: 母は日本語を話します (Haha wa Nihongo o hanashimasu) — は frames the mother as the established topic. The particle choice tracks whether the noun is new focus (が) or known topic (は).

Checkpoint

In the sentence 私は先生です (Watashi wa sensei desu, “I am a teacher”), what is the role of は?

Watch out

Do not confuse the two families of kinship terms. Use humble 母 (haha) / 父 (chichi) for your own parents, but polite お母さん (okāsan) / お父さん (otōsan) for someone else’s — or when addressing your own parents directly. Calling your own mother お母さん when reporting about her to an outsider sounds off in formal Japanese.

Checkpoint

Someone asks 誰がケーキを作りましたか (Dare ga kēki o tsukurimashita ka, “Who made the cake?”). Which reply best fits, and why is が used?

On the exam

The は/が distinction is tested constantly. A quick heuristic: if the information is new or being singled out (answers “who/what?”), lean が; if it is the established theme you are commenting on, lean は. Reading lots of authentic dialogue builds the intuition faster than memorizing rules.

Answer the 2 checkpoints as you read.