There is no such language.
Italy speaks the most Italian, as it is the official language of the country.
Usa
Brazil
india
a francaphone is a country that speaks french
equatorial guinea (although portuguese is only spoken by a minority there).
None. Purple is a color, not a language.
Romanian
The person that speaks for you in a foreign country is an Interpreter, but depending on the location they may say the name in that given language.
France speaks the language of French.
A monolingual country is one in which everyone speaks the same language and it is officially recognized as a monolingual country.