I guess not to further muddy the waters but saying Gallego and Catalan come from Castellano is extremely problematic (though people do this, it’s still difficult to square factually)
They all come from Vulgar Latin and depending on how you split it but Portuguese and Gallego come from a common ancestor and one has an easier time understanding Gallego if one speaks Portuguese than if one speaks only Spanish and Catalan would be a post until itself once we start discussing Occitan and Valencian, but it’s also not descended from Spanish (Gallo-Romance)
TLDR I really wish people would stop according Castellano as an official language and a bunch of languages that are as older or older than Castellano as some dialect descending from Castellano.
They all come from Vulgar Latin and depending on how you split it but Portuguese and Gallego come from a common ancestor and one has an easier time understanding Gallego if one speaks Portuguese than if one speaks only Spanish and Catalan would be a post until itself once we start discussing Occitan and Valencian, but it’s also not descended from Spanish (Gallo-Romance)
TLDR I really wish people would stop according Castellano as an official language and a bunch of languages that are as older or older than Castellano as some dialect descending from Castellano.
https://en.wikipedia.org/wiki/Galician-Portuguese
https://en.wikipedia.org/wiki/Catalan_language