My short answer: heck yeah!
My ability to speak a second language was my foot in the door at United. During 1996 it was a requirement that all new Flight Attendant applicants speak enough of a foreign language to pass a Berlitz "level 3" interview (conversational level). This requirement was relaxed during a period in the late '90s when United was on a "hiring binge."
While many new Flight Attendants do speak a foreign language, I do feel more could be done to encourage them to actually -use- it! This has been a sticky issue for both management and the union, though. In a contract proposal back in '96 United had hoped to increase the number of Flight Attendant/Interpreters per widebody jet from 2 to 4, but many senior Flight Attendants who weren't language-qualified did not like this amendment as this would decrease their chances to work on the higher pay international runs. The proposal was removed from our current contract.
United did increase the hourly bonus pay for language speakers, though: it's currently (a measly) $1.75, which can add up to around $1500 per year if the Flight Attendant works exclusively in that "language position." On select domestic flights such as SFO-MCO, LAX-LAS, JFK-MIA, or IAD-MSY we are offered "language incentive pay." While a tiny hourly bonus, it is a perk for any Flight Attendant who speaks, say, Japanese on the LAX-LAS flight that connects to the NRT nonstop. On one SFO-LAS flight a while back we had a 737 with about 95 of 100 seats filled with Japanese tourists. Not a rare sight in SFO or LAX, actually!
I wish United could increase compensation for bilingual Flight Attendants and increase the minimum number of Interpreters per flight, but those changes will be hard-fought, I believe. Also, I wish we could increase the number of bilingual customer service reps in the hub airports (I believe those reps are paid a small bonus, as well) and improve airport signage. I don't think we could ever do enough for either our foreign customer base -or- our bilingual staff, and I fear we never will....