ぞ / ぜ

ぞ and ぜ go at the end of a plain-form sentence and push it at the listener with force: "I'm telling you", "you know". A noun or な-adjective keeps だ before them. Both are rough, casual speech, heard mostly from men and boys and in fiction; never use them with someone you would speak politely to.

• × いい天気ぞ → いい天気だぞ

ぞ or ぜ

ぞ is the harder of the two. Said to someone, it warns or asserts, and can sound like a threat.

ぜ is lighter and more swaggering: it shares something with a friend rather than warning him. After the volitional form, ぜ makes a rough "let's".

Talking to yourself

ぞ also goes on a resolution you make to yourself – getting up, starting work, a match. In this use it is not aimed at anyone, and women use it as well as men.