The Maritime Flag Keyboard app allows you to set a custom keyboard that uses the keypad of your smartphone to write messages. Every key on the keyboard is a nautical signal flag and has a corresponding letter. 

With this keyboard, you will have a lot of fun writing your text messages and emails because you will be able to write in the nautical language. You can even write messages in different languages and have them translated.

You can even type in a language that you have not learned yet. The app has a lot of different flags and nautical symbols, so you can write any message that you want.