Lingua is a conlang builder for iPhone. Draw your letters with a finger, and the app turns them into a real font and a keyboard you can type with. Build a dictionary, a phonology, and grammar rules that actually conjugate. Post lines in your own script to a timeline where every post carries its letter shapes and a meaning line, so anyone can read it. Widgets put your own numerals and month names on the home screen. Free to start; paid plans add more.