Why are you silent with 〜てんだ
Grammar Explanation: Contracting 〜ているのだ to 〜てんだ
Being the first to arrive at the clubhouse after school, Yui decides to change her hairstyle and see how long it takes the others to notice when they arrive.
Sacchan arrives next and starts up a conversation. Yui simply sits there without saying anything.
- さっちゃん:
- 「なんで黙ってんだ！」
- "Why are you being silent!"
Here, 黙っているのだ is contracted to 黙ってんだ.