Language teaching & training
Language teaching may involve teaching a foreign language to students who share the same native language as you, or teaching your own language to speakers of other languages. Language trainers work in a variety of educational establishments from primary/elementary schools to universities, language schools and colleges.
There are many paths into language training: some people do a degree in a subject that interests them, then acquire a postgraduate qualification in teaching; some study education at undergraduate level; some start working as a teaching assistant, then later acquire professional teaching qualifications; some do some teaching while undertaking research.
Those teaching a foreign language need a near-native ability in that language, while a knowledge of other languages can be useful when teaching your native language to foreign students, especially to beginners.