When people talk, they use words to communicate with each other. Sometimes, different groups of people speak different languages. For example, in Vietnam, people speak Vietnamese.
However, a long time ago, Vietnam was ruled by the French colonizers. When the French came to Vietnam, they brought their own language, which is French. They started teaching French to the people there, and many Vietnamese people learned how to speak French.
Even though Vietnam is no longer ruled by France, French language still has an important place in the country. Many people in Vietnam today still speak French or have learned it in school. It is also used in official documents, like government papers or legal contracts.
So, even though Vietnamese is the most commonly spoken language in Vietnam, French also has a special place in the country's history and culture.