Smart-alecks sometimes ask why we Cheeseheads pronounce Brett Favre's name as "Farv."
Probably the same reason Wednesday is Wensday, and February is Febuary . . . lazy linguistics.
For that matter, it's prob-ab-ly, not prob'ly or prolly.
And it's re-mem-ber, not 'member
And irony is pronounced EYE-ron-ee, not eye-er-nee. It's ironic that folks don't have the same problem with "ironic."