Why is a language important to my future?
Unless you are intending to go into a career based around languages, such as a teacher or interpreter, no employer expects you to be fluent in a target language.
Basically a language skill makes you different to other job candidates in any career area. You are not just competing for jobs with your classmates, people from your city or country, but from all over the world. Brexit has made absolutely no difference to this.
But why cant I just use AI for languages?
AI is great for some things and not for others. For example AI is fantastic in the world of accountancy and can perform many tasks, but for actual global trade it has its limitations.
The whole world revolves around global trade, and for major contracts this means at some point people will have to actually speak to each other in real time.
Every business wants the customer to buy their goods or services and the human touch will always be far superior to any AI system, because people buy from people.