Linguistics is a macrofield concerning the science of human languages. The word "linguistics" is actu'lly an umbrella term for sev'ral more specialized fields such as phonology, semantics, and grammar. It is very useful to at least get a basic knowledge of them. Linguistics overlaps with most social sciences, some computer sciences, and other subjects. It is not being multilingual, but having knowledge of the universal traits and relationships that characterize language.
Image Sources:
1: John Pasden. Mandarin Tones Reference (3). 2006.
2: Jayarava. Indo-European Number five. 2012.
Indo-European migrations Wikipedia article