Many nationality adjectives in English are formed with the same suffixes. We see the same suffixes in Bolivian, Colombian, Russian, Venezuelan and in Bahraini, Bangladeshi, Iraqi, Pakistani and Yemeni. However, English also has a number of irregular nationality adjectives. Here is a list:
Ivory Coast Ivorian
San Marino San Marinese
United Arab Emirates Emirati
The nationality adjective of Kiribati is I-Kiribati. This is the most irregular nationality adjective in English. Congolese and Togolese are not so irregular, but they have an l before the suffix -ese. In Turkmen and Thai, we see nationality adjectives that are shorter than the names of the respective countries. This short list illustrates a few irregular nationality adjectives in English.