my portuguese and spanish are getting me in trouble with these words: 'o" in Portuguese is "the" and "carta" is letter in Spanish. Grrr!!
And 'o' in Spanish is "or"
As a native Spanish speaker who knows some Portuguese, I understand your pain. Your last name sounds Français.
I'm a native portugues speaker and i don't have a problem with the "o and un"
You speak 2 romance languages and you are learning a 3rd one so you'll probably get them mixed up