"Shona, like many vernaculars around the world, is considered uncool by the younger generations..."
No. The problem is some of us grew up in upper middle class families where speaking English and Shona was a norm. Unfortunately developing that deep Shona accent could not happen so now everytime we the young generation try and speak Shona it is met with giggles and snares like "hona mu salala uyo". So we now stick with English as we can laugh at your shona entagnled english which certainly feels better than you laughing at our english entagled shona :-)