That's because Spanish is a Romance language (i.e., derived from the Roman language), which was Latin.
There are also many similarities betweenSpanish and these three Romance languages: Portuguese, Italian, and French.
Several years ago, I traveled to Mexico with a friend who spoke Portuguese. He successfully used his Portuguese to speak with the Mexicans.
Incidentally, if you know English well, you will easily learn many Latin words.
After all, some 60% of English words derive from Latin or the Greek.
In addition, a number of Spanish words come from Greek (probably many via Latin).
Well... Of course we have no recording of this era, and no one went back through time to check... But there were many Roman and Greek grammarian at that time, which described quite accurately how their language was pronounced and gave us a pretty nice idea of how it sounded like.
I can't say for sure about the proper latin pronounciation (no one really can), but I believe your automatic inclination would relate to English pronunciation (your example in phonetics: /kəˈrɪkjʊləm ). In Swedish we don't add an extra j (that's y in English) even to curriculum and I've not read that it should be done in Latin either. So when you state someone your curriculum vitae in Latin you should likely drop the "y"!
I believe this phonological feature is called a u glide and is quite specific to English. (However, I can't seem to be able to confirm that with a quick look at wikipedia; somehow, they only talk about the opposite phenomenon: https://en.wikipedia.org/wiki/Phonological_history_of_English_consonant_clusters#Yod-dropping)
Well, I'm just a beginner too, but I'd say the answer is correct. "My" would be meum in one or another form. You made me try to find out what "Give me my cookie" would be, and I think it's "Da mihi crustulum meum"... but I'm really not sure of what case "meum" is. My grammar is rusty... But I believe it's accusative we need to use ( the my word would then be meam for femininum words, see the whole table at https://www.latin-is-simple.com/en/vocabulary/adjective/47/?h=meum ). Please correct me if accusative is not the right case to use. It's just mihi that is the dative part of the sentence, right? Implying that the cookie is to be given TO me.