The aim of our study is, basically, based on the study leaded by Merritt Ruhlen on world-languages-classification (classification presented in Ruh94). Proving that the methodology used by Merritt Ruhlen as well as the plenty amount of data used for the alike Greenberg's comparative method might have been a factor of constraint wouldn't be possible without the constitution of a probabilistic estimation. The application of this on Ruhlen's data allows us to highlight the fact that the demonstration leaded by Ruhlen among this book is probabilistically invalidated. We show that a drawing lots of the phonetic forms of the lexico-semantic referents gives the same results than him.