Deadlines and intakes
The Chilean academic year runs from March to December, with the second semester usually starting around August. Undergraduate admission for Chilean school-leavers is through a national entrance test; students with foreign secondary qualifications usually apply through special admission routes run by each university. Postgraduate programmes publish their own calls.
Work backwards from the permit: you need a regular student or enrolment certificate before you can apply, the application must come from abroad, and the criminal record certificate must be under 60 days old. The Universidad Católica's guide cites about 40 working days for an extension decision; initial applications have no published processing time, so apply as early as your documents allow.
Language you need
Degree programmes at Chilean universities are overwhelmingly taught in Spanish. Some postgraduate programmes, especially in science and business, are taught in English. Check the language requirement for your programme; universities set their own.
Chilean Spanish is fast and full of local expressions, and many international students take a few weeks to follow lectures comfortably even with good Spanish. You do not need Spanish for the permit itself, but SERMIG, the Civil Registry, landlords and most jobs work in Spanish.