Studies have show that from the age of 10, children are introduced to learning languages in a more academic way, less spontaneously due to traditional education practices. They are comfortable speaking their first language and have grown out of the child behavior of trying to get others to understand them with limited language ( as a 5 year old would due for instance).

Teenagers will be more scared of making mistakes, get embarrassed easily, and may fear their classmates making fun of them. Learning a foreign language seems more like a chore, an academic obligation , than learning for fun, passion, or benefit. Parents and teachers play key roles in motivating kids to learn a language.  It’s important to that teenagers develop an interest of learning a new language.  Parents can can, for example, establish family routines : doing an activity together once or twice a week, having a meal, doing a sport, going on a family outing where everybody tries to speak in the language  they want their child / children to learn, like French for instance.

Another idea would be to give them a book or game. Listening to or creating music,  and watching movies in a foreign language is also a really good way to improve language learning.
One of the best ways to anyone to learn a language, is traveling abroad , which many of us are already familiar with , but may not have had the opportunity to travel as much as we would like to.

Anything is possible however, so if it becomes a priority for you , and your family , things can be planned. There are many programs that exist to help teenagers and university students travel, live, and study abroad to learn a different language and culture.  The most important thing is that kids feel their parents interest , and passion , and support towards learning and experiencing a new language and have a great time.