When I was a kid, at home we spoke in a way pretty close to the "normal" TV presenter way, and my mom would get upset when we didn't. But at school, we spoke more like the kids from blue collar families, which involved some swearing we never used at home. Both probably qualified as dialects of their own, and I can still switch fairly easily between the two even though I've been speaking mostly the TV presenter dialect for many years. There's a good chance I'll revert to the blue collar dialect if I ever become $%?&$$ senile.

And in French, it is indeed a single letter, J, with a single pronunciation.

In English, the J sound has two components. In French, only the second component is produced.

>The "J" sound is combination of the "d" sound followed by the "zh" sound (as in the word measure).

For example, in English, Jerry is dzh - erry, and starts with a d consonant. In French it's zh-erry and there is no d.

So, "J'airius" would be pronounced "zh-air-ee-us".