Mermaids and languages

So, for the company that I work for they have decided they needed a mermaid, and I have volunteered. But I need to make this mermaid mine. Something that is completely original, unique, or how else you wish to say it. It needs to be new. So, I have decided that I must make a language. One that is beautiful and one that could be sung for I dearly love to sing. There so far isn't much of a problem, I have researched how to write a language, and to make one that is truly complicated but with a full history, I would need at least seven years. I began thinking that maybe I could just start creating something letter by letter and as the years go on, keep a record of all language changes but better it in any way I can. For some reason, every time the word "language" comes up, I think of the color blue, like ocean blue.