Japanese Grammar In Its Natural Habitat

だい

だい Japanese Grammar Lesson

Grammar Type: Particle

Essential Meaning: Interrogative marker in informal male speech

Construction: 

  • な-Adjective Stem / Noun + だい
    • E.g. どこが静しずかだい [What place is quiet?]
  • な-Adjective Stem / Noun + なんだい / だったんだい
    • E.g. どこが静しずかなんだい [What place is quiet?]
    • E.g. だれが先生せんせいなんだい [Who is the teacher?]
  • (Verb / い-Adjective) informal + んだい
    • E.g. だれが話はなすんだい [Who speaks?]
    • E.g. だれが食たべるんだい [Who eats?]
    • E.g. 何なにが高たかいんだい [What is expensive?]

Notes:

  • だい is an informal and masculine equivalent to the standard copula + か interrogative marker.
    • E.g. これはだれのだい。[Whose is this?]
    • E.g. これはだれのですか。[Whose is this?]
  • だい can only follow WH-question words such as だれ [Who], なに [What], どこ [Where], or どう [How]. In other words, だい cannot be used with yes-no questions (かい is used for yes-no questions instead).
  • だい can also be used in informal male declarative sentences to add emphasis. This usage comes across as boyish.
    • E.g. これは僕ぼくのだい。[This is mine.]
    • E.g. 僕ぼくも行いくんだい。[I will go too.]
  • だい is technically comprised of the copula だ plus the particle い. Due to the grammatical rules surrounding だ, only な-adjectives and nouns can directly precede だい. い-adjectives and verbs must instead be paired with んだい. (な-Adjectives and Nouns can also be used with んだい depending on the speaker’s intent). だい and んだい correspond to だ and のだ respectively.
  • Alternatively, informal interrogative sentences may be formed by simply articulating the sentence in the short verb form and with a rising inflection.　
    • E.g. 誰だれが行いく。[Who is going?]
    • E.g. どこが面白おもしろい。[Which place is interesting?]
  • In past tense questions, だった is typically used with rising inflection rather than だい.
    • E.g. Present: tense 新あたらしい仕事しごとはどうだい。[How’s your new job?]
    • E.g. Past tense : 新あたらしい仕事しごとはどうだった。[How was your new job?]

Example Sentences:

どの人ひとは先生せんせいだい。[Which person is the teacher?]

どの人ひとは先生せんせいなんだい。[Which person is the teacher?]

どこが静しずかだい。 [What place is quiet?]

どこが静しずかなんだい。[What place is quiet?]

何なにがおかしいんだい。[What’s funny?]

誰だれが行いくんだい。[Who is going?]

WILD Examples:

This song begins with the following line: やっと目めを覚さましたかい？それなのになぜ目も合わせやしないんだい？ [Did you finally open your eyes? If that’s the case, how come our eyes haven’t met?]

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