Chaika II Repair Results » Brampton Zum

It seems like all the Brampton busses are getting turned into Zums. I pronounce it like ‘zumm’ but my sister said she thinks it should be pronounced ‘zoom’. She says the two dots over the U make it sound like oo instead of uh. Which makes me ask what do the two dots over the M make the M sound like? Right? Say it with me. Brampton Zummmmmm.