Italian Pronunciation Basics - Stanford University
r. Italian r is either trilled or flipped, which is just a very short version of a trill. Double r is generally trilled, if the musical setting allows for it. Exactly when a single r should be trilled (and for how long) and when flipped is beyond the scope of this guide, but a good rule of thumb for single r is flip if between two vowels (e.g. in "fiori"), trill in other positions (initial ...