だって (reason)

• Reading: だって
• Romaji: datte
• Formation: だって + Reason clause

Meaning

A conjunction used at the beginning of a sentence to indicate a reason or justification for something previously mentioned. It translates as 'because,' 'after all,' or 'but the thing is,' and carries a slightly defensive or explanatory tone.

だって as a reason-giving conjunction typically appears at the start of an utterance in response to a question, criticism, or suggestion. It has a distinctly colloquial and slightly defensive nuance — the speaker is justifying their action, feeling, or position. It is softer and more emotional than から or ので, and frequently used when the speaker feels the need to explain themselves against perceived judgment. While common among younger speakers and in casual settings, adults also use it in informal conversation. It would be inappropriate in formal writing or business contexts. だって often introduces something the speaker considers obvious or self-evident as a reason.

Examples

1. 遅刻したのは仕方ないよ。だって電車が止まったんだから。 Being late couldn't be helped. After all, the train stopped running.
2. 行きたくないって言ったでしょ。だって興味がないんだもん。 I said I don't want to go. Because I'm just not interested.
3. 怒らないでよ。だって誰も教えてくれなかったんだから。 Don't get angry. Because nobody told me.

Usage Guide

Context: spoken, everyday

Tone: explanatory

Do Say

• 断ったのには理由があるの。だって条件が全然合わなかったんだもの。
• 泣いちゃったのは恥ずかしいけど、だってあの映画は本当に感動的だったから。
• 食べ過ぎたのは反省してる。だって久しぶりの手料理だったんだから。

Don't Say

• だって、弊社の方針といたしましては。(Using colloquial だって in formal business speech — use なぜなら or と申しますのも) → と申しますのも、弊社の方針といたしましては。
• だって天気がいいです。(Using だって without a preceding statement to justify — it responds to an implicit or explicit challenge) → 外に出ようよ。天気がいいから。

Origin & History

だって is a contraction of だと言って (saying that it is) or であっても (even if it is), which grammaticalized into a conjunction introducing reasons. Its colloquial and slightly plaintive tone reflects its origin in spoken argumentation.

Cultural Context

Generation: All ages

Social background: Universal