For visitors/travelers coming to Singapore, this is how you order your local coffee.
To read more about the context, the New York Times published a great read about having an authentic, local Singaporean experience here.
I personally go for Kopi-O-siu-dai. That’s black coffee, less sugar.
KOPI Coffee with sugar and condensed milk.
KOPI C Coffee with sugar and lighter evaporated milk instead of condensed milk. (The “C” stands for “Carnation,” the longtime go-to brand for most kopitiams.)
KOPI KOSONG Coffee with no sugar (“kosong” is zero in Malay).
KOPI O Black coffee.
KOPI O POH Diluted black coffee with sugar.
KOPI PENG Coffee with sugar and condensed milk, over ice.
YUAN YANG Half-coffee, half-tea combination, with sugar and condensed milk.