Learning local language.
While some of a culture's knowledge, rules, beliefs, values, fears, and anxieties are taught explicitly, most of the information is absorbed subconsciously.
Communicating across cultures is challenging because knowledge of cultures is essential for facilitating interaction with people. Language has always been an important source of communication. Moreover, language plays an important role when you want to express your opinions and attitudes to the person you are talking to and for that, it is essential to learn the local language for effective communication.