Since the beginning of times there have been discussions about linguistic diversity and the communication among men. One can easily say that Plato (427 - 347 b.c) and Aristotle (384 - 322 b.c) led both linguists and philosophers to constantly search for explanations concerning the origins and common characteristics of the many languages that exist in the world. It seems that the obsession to find the one language from which all others are supposed to derive still persists, as does the desire to return to it. This is the reason why philosophers and linguists fundamentally support the development and use of a single language. Such a language would make possible the communication among men on a universal level, irrespective of their birth place, culture or mother tongue. In other words, a free and democratic communication could take place and there would also be free access to knowledge. One of the Enlightenment`s ambitions could therefore be achieved: men would be able to perceive reality autonomously. Taking those issues as a starting point, a historical study was developed to investigate the search for a single language, from the Enlightenment until contemporary times, particularly after the advent of Internet. For this purpose, this study begins with Kant`s conception of Enlightenment, followed by the ideas of two of his contemporaries, Condorcet and Condillac, who suggested the use of a universal language as a means for man to reach Enlightenment. The study discusses universal language projects of the 19th and early 20th centuries and points out the reasons for their failures. It proceeds with a presentation of the attempt to make English the worldwide language of communication from the second half of the 20th century until the Digital Revolution. It argues that, at this stage, what matters is no longer the development of a single language, but of a free way of communicating, regardless of the language spoken and with unlimited access to knowledge. This is more clearly seen with the onset of the third generation of the Internet, known as the Semantic Web, which is recuperating the ideals of the Enlightenment and has been proving to be a possible way for communication on a universal level and for man`s Enlightenment.