>>33550309They have a small team made up of translators, marketers, and reps from Pokemon Japan who sit around at a table trying to think up names for the things.
One of them gave an interview about it once and told the story of Piplup's English name. Everyone was tired and wanted to go home, so they just wanted to throw together a name for the damn thing. Since its Japanese name means something like "the sound a rock makes when it falls in water", they decided "ploop" was a good English equivalent. Hence, "Piploop". The next day everyone came back to the office after a night of sleep and realized it sounded too much like "poop", so they just changed the vowels and ran with it.