A person (such as myself) who soon starts speaking in any accent they hear spoken. It does have to be fairly realistic -- no terrible movie accents -- but I start speaking Received Pronunciation British English after watching Doctor Who, go back to my native southern accent when I visit my family in the Carolinas (though I had no trouble losing it when I first moved to urban Florida), and had no trouble swapping from my high school Latin teacher's Spanish-accented Latin to my college instructors' much more English-influenced pronunciation.