It will help a great deal, and get you on good international trips while still very junior...if you want to be a flight attendant.

It will not specifically help you get a pilot job in the US, other than to make you more well-rounded for the interview. It might help you get a job overseas if you speak the local language, but there are many other criteria which you have to meet to be considered for non-US airline jobs. If you meet all the criteria and think you are eligible for employment with a certain foreign airline, it would not hurt to learn the local language.