What is the most commonly used communication device?

This is a tricky question! It depends on how you define "communication device" and "commonly used." Here are some possibilities:

* Smartphones: These are probably the most universally used communication device for things like texting, calling, and accessing the internet.

* Computers: While not strictly "communication devices" in the same way as phones, computers are essential for communication through email, video calls, instant messaging, and social media.

* Televisions: While not directly used for two-way communication, televisions are a major source of information and news, making them a crucial communication tool.

Ultimately, the "most commonly used" communication device depends on the context and how you define communication.