A new conlang concept

The concept is a language which consists only of vowels & tones

Pros: It will help people with speech impediments to communicate. It may have scientific value. Cons: It will probably be somewhat difficult to learn. In some languages, English included, tones used usually semi-conciously serve only to change certain nuances in what is said and not meaning as it would in this project.
Native speakers of such tonal languages as Mandarin, Cantonese, Vietnamese, etc. will probably learn it easier than those who speak western languages.