Thanks! oh and here you go Marcus! in case you started to doubt our superior intelligence haha:
taken form good old wikipedia (had to do it, you were getting on my nerves...)
Suffixation
The English language uses several models to create demonyms. The most common is to add a suffix to the end of the location's name, slightly modified in some instances. These may be modeled after Late Latin, Semitic, Celtic or Germanic suffixes, such as:
-(a)n (countries / continents: Africa → African, Albania → Albanian, Algeria → Algerian, America → American, Andorra → Andorran, Angola → Angolan, Antigua → Antiguan, Armenia → Armenian, Asia → Asian, Australia → Australian, Austria → Austrian, Barbados → Bajan, Bolivia → Bolivian, Bosnia → Bosnian, Brunei → Bruneian, Bulgaria → Bulgarian,