Cultural competence doesn't come with simply learning a language. There are many important aspects to it that make a person culturally competent. This has to do with understanding body language, sociolingual which include cultural norms and expectations, among many others. If someone does not understand these language in these contexts it can get them into trouble and make them look ignorant as well as insulting.
This made think about how foreigners adjust to new countries- they have to adjust to a completely different lifestyle (usually) and then learn how the people of that country interact and what they mean by their actions, gestures, and understand their speech. This speech includes slang and other technical language parts such as grammar. It takes a long time to get used to them and when it clashes with pre-existing cultural understandings it may be hard to assimilate because one would want to resist changing their personal beliefs.
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