And everyone says the legacy carriers are mismanaged...

JetBlue has the right idea. If they want their current flight attendents to learn spanish, the best way to do that is to send them to a foreign country for a several weeks. That is the best way to learn a foreign language. I bet JetBlue expects the flight attendents to pick up spanish in a few days. THAT WON'T WORK! You need atleast 3+ or so weeks to pick up some.

How much does it cost to pay a flight attendent for 3+ weeks, and provide a hotel for them in Spain??

How about hiring flight attendents that speak spanish??? United went to hire 2,000 flight attendents, and they got 7,500 apps in just 3 days. And 50% were bilingual! Maybe because everyone wants to work at a carrier like United rather than JetBlue... (Nevermind, I will stop bringing that up).

I hope that JetBlue does not throw away money on this project. Just hire bilingual flight attendents if that is what you want.