Glossika, a great program, a little less fun than Duo but very useful andit works well. has a few minority languages free, some that Duo does not even offer. Catalan and Welsh are amoung them. i'm learning Catalan an it is on point. just letting you guys know
It looks like at least some Catalan content is indeed free:
"Since we care about language preservation, you get unlimited spaced repetition practice for select languages for free. Languages currently offered and location where spoken: Catalan, Manx (UK), Welsh (UK), Kurdish (Iraq), Taiwanese Hokkien (Taiwan), Hakka (Taiwan), Wenzhounese (China)."