“Fundamentally, a flag is a symbol of a country. (It could also be a symbol of an administrative area or a society or organization or movement, but such flags are not used as symbols of languages, with rare exceptions like Esperanto.) Naturally one could use a flag a symbol for the country e.g. in a list of links to information related to various countries. Whether it is wise to do so depends on the context. Typically people know names of countries better than their flags, so usually a flag isn’t such a great symbol communicatively. What we discuss here is the use of flags for languages, and such usage is plain wrong.”