"Saya tinggal di Amerika Selatan."
Terjemahan:I live in South America.
She is pronouncing live wrong. She is pronouncing as an adjective not a verb. Proper ptonunciation in this example should sound like "le-v", not "lai-v".
Yes normally if you say America people will know you are talking about USA. However South America is not USA, it is the continent of South America. If you are referring to south USA you say American South or Southern USA or Southern States etc. Same with North America which refers to the continent, not the northern USA.