At first I thought this might be fun/helpful for people writing fantasy novels for digital distribution. Maybe you want a new elf-language, but don't want to blow a ton of time on actually composing the thing - this makes it easy - just drop in all your elf text and the thing will not only give you the translation, it will provide a word for word glossary of new elvish.
Then I realized this could be useful for anyone who wanted to communicate a secret message in public. Maybe you want to tell your kids to shutup, or your husband that the guy ahead of you in line smells bad.
Maybe you're a 12 year old girl who needs a secret language for your girls-only club. Lingua Esoterica will give you your own language - totally unique to you.