ご (with Sino-Japanese words):
お (with native Japanese words):
Note: Some words conventionally take only ご or only お; a few accept both.
The prefix 御 (ご / お) is used primarily to show respect (そんけいご尊敬語). It is attached to something that belongs to the person addressed.
However, it is not used when talking about one's own belongings. A waiter would say ごちゅうもんご注文 in reference to the customer's order, but the customer would refer to it just using ちゅうもん注文.
It can also be added to words that don't describe things owned by the addressee. This makes the speech more polite or more refined (びかご美化語).
ご is used with Sino-Japanese words (words of Chinese origin). お, on the other hand, is used with native Japanese words.
Unless the context is very formal, お is usually written in hiragana. ご can be written in kanji even in less formal contexts.
Some words take these prefixes regardless of who is speaking to whom. This generally pertains to ordinary items which may have a certain cultural significance (おちゃお茶, ごはんご飯).
For some words, the prefix became their integral part: おにぎり, おまえお前, おはよう, おなら, ごめん, ごはんご飯.
In some cases, the words have different readings with and without the prefix: りえき利益 vs. ごりやく御利益
Although foreign/katakana words seldom take the honorific prefix, there are some exceptions: おびいるビール, おかあどカード, おといれトイレ, おたばこタバコ, おずぼんズボン, おそうすソース
In some cases, 御 can have other readings:
御 + Noun shows respect for the person or entity associated with the noun.
In honorific speech, 御 + Adjective is used for adjectives describing personal characteristics or states of the subject (such as youth, health, calmness, and similar traits). In polite speech, it can be used for other kinds of adjectives as well.
To describe a person with the honorific version of a na-adjective, you can use the honorific copula でいらっしゃる.
御 + Adverb
御 + Verb appears in honorific or humble forms to elevate the listener or lower the speaker: お/ご〜する or お/ご〜になる.
As previously mentioned, the general rule is that ご is used for Sino-Japanese words and お is used for native Japanese words.
Words that use お are often related to food, drinks, and everyday tasks (this also applies to many of the exceptions listed in the table below). For example, おこめお米, おつまみ, おみずお水, おさけお酒, おてがみ手紙, おかねお金.
Family roles also take the prefix お: おとうさんお父さん, おかあさんお母さん, おにいさんお兄さん, おねえさんお姉さん. Note, however, that おとうと弟 or いもうと妹 don't pair with the prefix, as you traditionally don't show the same amount of respect to younger people.
Examples of words that use ご: ごかぞく家族, ごけっこん結婚, ごじゅうしょ住所, ごいけん意見, ごちゅうもんご注文
_Note that this list is not exhaustive and that there are even more exceptions._
| Word | Meaning |
|-|-|
| おけいこお稽古 | practice |
| おたくお宅 | home |
| おちゃお茶 | tea |
| おでんわお電話 | telephone call |
| ごゆっくり | take your time, enjoy your stay |
| ごもっとも | you're right |