English says two coffees but two cups of coffee, and two sheets of paper rather than two papers. Indonesian does this systematically: a measure word sits between the number and the noun.
The three that matter
orang for people
ekor for animals
buah for objects
dua orang turis ‘two tourists’
tiga ekor ayam ‘three chickens’
lima buah rumah ‘five houses’
Ekor literally means tail, and buah means fruit. Nobody thinks about that any more, in the same way English speakers do not picture a head when they say fifty head of cattle.
The others you will see
lembar or helai for thin flat things: paper, cloth
batang for long thin things: cigarettes, trees, pens
butir for small round things: eggs, grains
potong for slices and pieces
You do not need to produce these. You need to recognise them on a receipt or a menu.
When to drop them
In everyday speech, buah is dropped constantly.
dua rumah ‘two houses’. Perfectly normal.
Orang and ekor survive better, because the distinction between two people and two things is one speakers care about.
The safe rule for a learner: use orang for people, drop the rest, and nobody will notice.
Counting people politely
Asking how many people, in a restaurant or a car:
Berapa orang? ‘How many people?’
Berdua. ‘Two of us.’
Bertiga. ‘Three of us.’
Those last two are ber- attached to a number, and they mean “as a group of n”. You met ber- in the affixes chapter; this is one of its neatest uses.
The one that is not a classifier
se- attached to a classifier means one.
seorang ‘one person’
seekor ‘one animal’
sebuah ‘one object’
Same se- as in sebelas, seribu, sehari. It turns up everywhere once you notice it.