Sudan
noun: Sudanese (singular and plural)
adjective: Sudanese
Suriname
noun: Surinamer(s)
adjective: Surinamese
Swaziland
noun: Swazi(s)
adjective: Swazi
Sweden
noun: Swede(s)
adjective: Swedish
Switzerland
noun: Swiss (singular and plural)
adjective: Swiss
Syria
noun: Syrian(s)
adjective: Syrian
Taiwan
noun: Chinese/Taiwanese (singular and plural)
adjective: Chinese/Taiwanese
Tajikistan
noun: Tajikistani(s)
adjective: Tajikistani
Tanzania
noun: Tanzanian(s)
adjective: Tanzanian
Thailand
noun: Thai (singular and plural)
adjective: Thai