To be honest, I don't really see the issue with sounding it out as "jal a peen oh". We don't pronounce every single word we've taken from another language in the same way as it was originally, so if it's close enough, I don't mind too much. I personally pronounce with the soft J as a H but if someone said it the way you're talking about, it wouldn't bother me.
There's a similar situation with Subway's Chipotle Chicken/Chipotle Southwest. Should be pronounced chip-oat-lay but a lot of people come in and say it as chip-ot-ul. Since it's not a common word in England, it's not surprising that people will sound it out that way. That's close enough for me, at least it's an attempt at pronouncing how it's actually spelt. There's a lot of people who will ask for "Chipolata Southwest", which is a much more worrying issue