General silence:
* Be silent: This is the most straightforward option, meaning to not speak at all.
* Hold one's tongue: This implies actively choosing not to speak, even though one might have something to say.
* Keep mum: A more informal way of saying "be silent."
* Say nothing: This simply means not saying anything.
Not speaking a specific language:
* Be mute: This implies a complete inability to speak, often due to a physical condition.
* Be speechless: This suggests an inability to speak due to shock or awe.
* Not utter a word: This emphasizes the absence of any verbal communication.
Expressing oneself without words:
* Communicate nonverbally: This encompasses all forms of communication without words, like body language, gestures, or writing.
* Convey through actions: This focuses on using actions instead of words to communicate.
* Express oneself silently: This implies communicating emotions or thoughts without speaking.
The best word to use will depend on the specific context and what you want to convey.