Nowadays, there is a growing need for dissemination of documents in several languages. Machine translation is usually regarded as a possible solution for this, but so far it cannot provide acceptable translations of unedited texts. Several methods which involve human participation in computerized processes of translation have been proposed, but none has given really satisfactory results (except in some restricted contexts). In the UTL (Universal Translation Language) project, which we present here, we propose a new approach to multilingualization, based on the usage of an artificial unambiguous human language in which the human translator writes the source text, and then gives it to the machine to translate into other languages. The nature of this constructed language, which is optimized for this role, ensures the high quality of the results rendered by the computer.