If a word exists in at least three of the "control" languages, English, French, Spanish, Italian, German and Russian, it is automatically accepted as an Interlingua word after it has been standardised on the basis of its etymology. For example, the word which appears as "natio" in Latin, "nation" in English and French, "Nation" in German, "nacio'n" in Spanish, "nac,a~o" in Portuguese and "natsiya" in Russian become "nation" in Interlingua.

Because it consists of international words, which are mostly Latin in origin, Interlingua can be understood by millions of people who have not studied it and who may never even have heard of it by name. That is why it is so useful for communication with the local population in countries of Southern Europe and in Latin America.

Because Interlingua is nobody's mother tongue (yet), it does not give an unfair advantage to the speakers of any particular language and can be introduced as an official language in international organizations. Not only is it neutral, but also very easy to learn because of its simple and regular grammar and its vocabulary of words which are already familiar.