For 25 years, I taught "General Language Studies" at the high school level. This subject has replaced Latin as a compulsory subject for all humanities students in Sweden. It covers the international vocabulary words that have been adopted by all European languages. This vocabulary, in combination with an extremely clear and simple grammar, is the basis of Interlingua. To bring the subject to life for my students, I used Interlingua texts in my classes - to great advantage.
I also held each year an optional class in General Language Studies, normally attended by natural science students. Many, many of these students have later told me how really useful these studies were for them later on. Virtually every word in Interlingua (and its breakdown in the topic 'word formation') has helped them in studies of English, French, Spanish, Italian, Portuguese and Latin. (What is more, many people do not realize that a large number of these international words even exist in German and the Slavic languages.)
Therefore: Include Interlingua in the curriculum!
Four hours a week for the first year is enough to reach level C (proficient user) in practical communication. But the greatest gain is that Interlingua gives a solid linguistic foundation for studies of other languages. The simple grammar ensures that you are not put off learning other languages and at the same time gives you insight into the structure of several languages.
This lower learning threshold for Interlingua is doubly rewarding because you then need less time to master languages that normally require years of study. If you learn Interlingua, you understand directly at least 65% of the vocabulary in a French, Spanish, Portuguese, Italian or Latin textbook.