Japanese family vocabulary asks one quiet question: whose family are we talking about?
Japanese has a familiar word and a humble or neutral word for many relatives. You call someone else’s mother お母さん (okaasan · mother), but when speaking about your own mother to an outsider, 母 (haha · my mother) is often more natural. The distinction is about viewpoint and politeness, not affection.
The core pairs
Otoosan / chichi are father; okaasan / haha are mother. Oniisan / ani are older brother; oneesan / ane are older sister. Younger siblings usually use otouto and 妹 (imouto · younger sister) without an honorific prefix when describing your own family.
Speaking to the person directly
Children call their parents okaasan and otoosan, and adults may continue to use those forms inside the family. A shop worker may call an older male customer otoosan in a warm, non-literal way, especially in a family setting. Context decides whether a word is a relationship label or a form of address.
Children and relatives
Musuko is son, musume daughter, kodomo child, and ojiisan / obaasan grandfather / grandmother or an older man / woman depending on context. Japanese speakers often clarify the relationship with watashi no (“my”) or a name when ambiguity matters.
Learn the viewpoint, not a table
Write two sentences for each relative: one about your own family and one about another person’s. For example, haha wa Osaka ni sundeimasu (“My mother lives in Osaka”) versus Tanaka-san no okaasan (“Tanaka’s mother”). This practice makes the social angle visible and prevents the common mistake of using the familiar form everywhere.
Names change by situation
The same person can be haha when you describe your own mother to someone outside the family, okaasan when you speak to her, and Tanaka-san no okaasan when you mention another person’s mother. This is not a rigid rule for every family. Some adults use familiar forms in casual conversation, so listen to the relationship and setting before copying a form.
Grandparents, uncles, and cousins
Sofu and sobo are formal words for one’s own grandfather and grandmother; ojiisan and obaasan are common when addressing someone or describing another person’s relatives. Oji means uncle and oba aunt in a neutral or humble description. Cousins are itoko. When the relationship is complicated, Japanese speakers often add a name or age order rather than relying on one word alone.
Practice with two viewpoints
Choose a family photograph and describe it twice: first as your own family, then as a friend’s family. Add watashi no, Tanaka-san no, or an honorific prefix where appropriate. This makes the viewpoint shift automatic and prevents a vocabulary list from becoming a collection of context-free translations.
Sources & further reading
Japanese-language sources — what Japanese readers read about this, not what's written for visitors.
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