use the
waa-sappenin technique.
https://www.youtube.com/watch?v=OlkWpl0HmTU
start from the pronounciation, then work your way down.
i'm srsus btw.
i speak fluently w/o accent and i'm completely self-taught. although the full-immersion system would be better, it's unrealistic given the short time and her age. what can really do it is phonetic mechanism memory .. or waa-sappenin.
i start my "students" with a single word they get to pick themselves. once they get that down to full proficiency (perfect pronunciation and enunciation) you branch out with other words which are linked to the first (e.g. "baseball" -> "game") until you get to full sentences. when a full sentence is memorized you add a second, a third ..
getting the pronunciation + enunciation perfect is the key, because the actual "mechanical" aspects of the language are learned, subconsciously, prepping the brain for similar events. just like muscle memory, but for the brain + mouth.
us italians are absolutely terrible at foreign languages; i've met a ton of my connationals who have a an extensive english vocabulary, and yet cannot actually speak english. i'd rather have a student that can speak the language, but has zero vocabulary - it can always get extended with time + use. this phonetic-muscular-memory system preps the the correct area of the brain for english (different languages use different areas of the brain), facilitating the storage of new words.
given that my english vocabulary is several times more extensive than most native speakers, i'd say it works.