Yup! It's called a keyboard. The letters displayed are there for you to press so that you can send messages with words. Here, look at this.

[Give him a moment, he's setting up his own device for a text. Soon Korra's CereVice will receive a message that simply says Like this.]

Texts are sometimes easier to work with than calling a person, especially when you only need to say one quick thing. In my world there's also instant-messaging but that's through computers, usually.