That's why we talk about people having an "ear" for language. Babies hear the phenomes of every language but soon learn to hear only those of their own. Someone with an ear for language often has kept the ability to hear and therefore copy other/unfamiliar sounds. I studied Spanish with various S Amer. teachers then went to Spain. It took me a week to re-tune my ear to the local sounds. V sounded like B, B was half way in-between the two. The R was rolled and the RR rolled so hard it sounded like a D, the hard C was a K sound and the soft C was a Th while the S was not Th or Sh but wasn't quite an English S either. I do like getting the pronunciation close enough to pass for, well obviously not local but not too distinctly N Amer.