My parents say ON-velope. Rather than EN-velope. Cin-a-MAR, rather than Cin-a-ma.
Slightly differently, they also say 'trod on' rather than 'stepped on'. I know it's not incorrect, I just hate the posh way they say trod and think it's a horrible word!
All the above drives me crazy! Aaaaarrrghhhh
Inspired by the theatre thread!