मुँह में दही जमना

You use it as a question to poke fun at someone. You can say Kya tumhare muh mein dahi jama hai?. This translates to 'Has curd set in your mouth?'. It is a rhetorical question. You are not actually asking about dairy products. You are asking why they are not answering you.

Use it when a friend is hiding a secret. Use it when a child is caught being naughty and stays silent. It works great when someone is shy during an introduction. It is perfect for lighthearted teasing among peers. You might use it if a colleague is unusually quiet in a meeting. It adds a touch of humor to a tense silence.

Do not use this in very serious or tragic situations. If someone is silent due to grief, this is insensitive. Avoid using it with high-ranking bosses or elders you don't know well. It can sound a bit cheeky or rude. Do not use it if someone has an actual speech impairment. It is meant for psychological silence, not physical difficulty.

In Indian households, curd (dahi) is a staple food. It takes hours to set and becomes a thick solid. The metaphor suggests that something has solidified in your mouth, making movement impossible. Curd is also seen as cooling. Perhaps the person's 'hot' arguments have cooled into a thick, silent block of curd!

You will mostly hear it as a question: Muh mein dahi jam gaya hai kya?. Sometimes people just say Muh mein dahi jama kar baithe ho. This means 'You are sitting there with curd set in your mouth'. Both versions carry the same teasing tone.