It's definitely a problem for us non-native speakers, but not really for native speakers. Argentinians probably have an easier time understanding someone from B

It's definitely a problem for us non-native speakers, but not really for native speakers. Argentinians probably have an easier time understanding someone from Brasil speaking Portuguese or an Italian speaking Italian than I do a Puertorriqueño or Spaniard speaking Spanish. Though it does remind me of the time a friend and I wandered into a Billy Connolly (the Scottish comedian) stand-up performance in Dublin, and we both spent the first 45 minutes not being able to understand a single word the guy said. Which was doubly frustrating since the Irish audience around us was laughing their asses off.