The Faculty of Arts of the University of Lisbon (FLUL), also located on the University City campus and a few metres from the Faculty of Sciences, offers Portuguese language courses to exchange students (Erasmus+, for example) who are enrolled in one of the schools of the University of Lisbon. The main objective of these courses is to teach the basic rules of the Portuguese language in order to facilitate students' day-to-day lives in attending classes, most of which are taught in Portuguese.
Enrolment in these courses must be done in person at the Institute of Portuguese Culture and Language (ICLP), but only after the student has registered with the External Relations Division of FLUL.
There are other courses aimed at international students who wish to learn Portuguese. Contact the ICLP directly for more details:
Institute of Portuguese Culture and Language
Faculty of Letters, University of Lisbon
1600-214 Lisbon
Portugal
You can also find other institutions/associations that assist in teaching Portuguese, such as Erasmuslisboa, CCL - Centro de Cursos Livres or Lisbon Language School.