Can someone ELI5 Palatalization and how it permanently changes languages?
Firstly, my background: I am an Early Medieval/Late Antique historian by trade, but I have always been tangentially fascinated by linguistics, but it is much more of hobby for me than history, so bear with me if this is surface level or dumb. I also tried searching for this answer everywhere and I did not see one, so forgive if this has been asked/answered before!
I was recently reading about Celtiberian as I am deep in a Roman rabbit hole, which sent me down another rabbit hole about the "Insular/Continental" and "P-/Q-" hypotheses about the dissemination of Celtic languages across Europe and I kept running into the term "palatalization" being one of many factors on how and why languages change. This sent me down another rabbit hole...
I read up on the wikipedia page about this and I am left lacking with an explanation for why humans do this, and more importantly, how these (what seem to me) sloppy pronunciations of words ends up sticking and forming new languages. One example I see mentioned a lot is Latin centum (/k/ sound) changes to Italian cento (/s/ sound) as a result of palatalization. I understand that it has something to do with our tongues slipping, for lack of a better term, but like... didn't people realize that they were pronouncing the words wrong? and for that matter, is palatalization so foreign to me because we have modern, systemized, languages today with dictionaries, thesauruses, etc. that would make it easy for someone to correct themselves? I know sometimes I say "didya know?" instead of "did you know?", but I don't think anyone nowadays is going to argue for adding "didya" to the dictionary.
sorry if this is rant-like - like I said, I am deep in rabbit hole-ception while I am typing this and I have a million questions a second it feels like haha any help, answer, or point in the right direction would be extremely helpful!