VIsitors is obviously not a an adjective. It is a noun in plural form.
Vietnamese is the proper adjective for Vietnam.
The proper adjective for the proper noun 'Celt' is Celtic.Please note that a proper noun and a proper adjective is always capitalized.
Ghanian is the proper adjective for Ghana.
Since spice isn't a proper noun, it can't have a proper adjective. The adjective of spice is spicy.
Since writer is not a proper noun, it doesn't have a proper adjective.
The simple subject in the sentence is "visitors." "Many" is an adjective describing the number of visitors, not the subject itself.
The proper adjective for Portuguese is "Portuguese."
The proper adjective for Haiti is Haitian.
The proper adjective for southwest is "southwestern."
Vietnamese is the proper adjective for Vietnam.
The proper adjective for George is Georgian.
The proper adjective for Siam is Siamese.
Freudian is the proper adjective for Freud.
The proper adjective for Georgia is Georgian.
The proper adjective for Mayan is "Mayan."
No, old is not a proper adjective. A proper adjective is an adjective derived from a proper noun, such as Swiss cheese, Bolivian pottery, Chinese silk, etc.
France is always a proper noun it is never a proper adjective (what is a proper adjective? The adjective is french. I like french food