The proper noun for the proper adjective 'Portuguese' is Portugal, the name of a specific country.
Polish is a proper adjective that can be used for Poland.
Danish
HAH-meesh is a pronunciation of 'Ramish'. The proper noun isn't native to Portugal. But it easily may be pronounced in the way given, according to the pronunciation rules of Portugal and of the carioca accent of Rio de Janeiro, Brazil.
Hamiltonian is the proper adjective for Hamilton.
The noun form for the adjective Portuguese is Portugal. The noun Portugal is a proper noun, the name of a specific place. The word Portuguese is a proper adjective and a proper noun (a person of or from Portugal). Proper nouns and proper adjectives are always capitalized.
The proper noun for the proper adjective 'Portuguese' is Portugal, the name of a specific country.
The proper adjective for southwest is "southwestern."
The proper adjective is Haitian.
The proper adjective for Portuguese is "Portuguese."
Vietnamese is the proper adjective for Vietnam.
The proper adjective for Georgia is Georgian.
The proper adjective for George is Georgian.
Freudian is the proper adjective for Freud.
Mayan is itself a proper adjective.
The proper adjective for Siam is Siamese.
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.