Many thousands of people know Interlingua , and Interlingua speakers say that millions can understand it ( read texts in it and listen to someone talk in it ) without having to learn it first . Interlingua is promoted internationally by the Union Mundial pro Interlingua . Periodicals and books are produced by many national organizations , such as the Societate American pro Interlingua , the Svenska SÃ llskapet fÃ r Interlingua , and the Union Brazilian pro Interlingua .