Forming adjectives and nouns.
[Old French -eis, based on Latin -ensis.]
Adjectives denote an inhabitant or language of a city or country: Cantonese, Japanese, Maltese, Nepalese, Taiwanese, Vietnamese, Viennese. Pekinese, from an older transliteration of the name of the city now usually called Beijing, often refers to a breed of dog brought to Europe from that city; Siamese is from an older name of the country now called Thailand, and now usually refers to a breed of cat or to twin babies conjoined at birth.
Nouns are often derogatory, referring in particular to written language from a given source that is considered to be in a poor style: journalese, officialese (and bureaucratese), legalese, novelese (a style of writing supposedly characteristic of inferior novels). New examples continue to be formed: computerese (the supposedly incomprehensive technical jargon of computing), jargonese. A rare example that is not derogatory is motherese (child-directed speech).