pj997,
Though having a second language on your CV may be a plus point,unfortunately it's not a MAJOR one.Far more, it's what's on there in terms of flying experience.There are those who appreciate it such as Ryanair,but at the end of the day it matters not a stuff compared with the ability to produce a 737 rating out of your pocket(for them at least).
Without wishing to sound negative(though I do seem to)hours in the logbook and the type of flying with which they were gained says more to an employer.
However,certainly faced with two potential candidates with the same experience,one with a second language and one without,the former will probably have the advantage.
Most normal interviewers(if there are any!) are asking the question to themselves"would I like to be stuck on a flightdeck for four hours with this person?" So personality and experience,unfortunately, are king.
Anyhow,best of luck mate.
AH