universities dont offer Spanish courses. You have the option of the Paraguayan - Japanease Cultural Centre in Asuncion that runs "Castellano" under Idiomas image. The course costs about 50 USD per month Monday to Fridays.
It doesnt says how many hours but probably 1 1/2 h per day.
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thanks a lot man, many people said good things about para-jap cultural centre, for language learning,
if you know their website pls let me know .