"Soy de México" means "I am from Mexico".
Soy is used for nationality. I am from Spain
soy de... means: I am from... literally: "I am of..."
Yo soy de Portugal means 'I am from Portugal.'
i am from...
If by America you mean USA Soy de Estados unidos if you mean the continent soy de America
I am from here(abouts)
It means: Where am I from? You are asking yourself what is your own origin or from what country are you.
No soy de Milano would translate into something along the lines of "I am not from Milano".
Soy de la in English means I am of. Ex. I am of Spanish heritage. (Soy de la Spanish heritage.)
To say you are from Miami, say, "Soy de Miami." "Soy" means "I" while "de" means "from". So "Soy de" means "I am from".
yo soy de Florida means: I am from Florida.