Improved understanding of the world
Learning a new language gives you a greater global understanding of the world we live in. Even by learning a few phrases, never mind a whole language, you will access many fascinating cultures around the world and understand the differences between the two countries.
You will have access to a whole new array of film, music and literature, and a greater understanding of the history and culture of the nation and ultimately a better understanding of the way the world works, including politics and security.