An experiment with phonetic writing

[ololololo]

I had never heard pronunciation of aujourd'hui” as “ujuvi” but I heard it on the radio today.

This is how a person who doesn’t know French well might pronounce it. Purely theoretically, in fast speech, a person might not pronounce all the sounds, which could result in, for example, the sound “r” being omitted.
A more accurate phonetic rendering is “oujourdvie,” but I don’t think the person who is learning French in our metaphor would be able to write it that way.