Premise: To a Western ear, the most predictable of language traits, perhaps, is the well-advertised Japanese use of r for our l .  Indeed, in my travels about Honshu during a three-month visit, I did hear  coinrocker,   see you rater,   Adurt Graphics  (dirty books),  blackwrrants  (hit-and-miss rendering of black walnuts),  Coffee Corombia  (a chain of coffee shops), and  Coconut Glove.

Hypothesis: To the Western ear, the least predictable of language traits are perhaps the most well-advertised use of r.
Relation: contradiction