Twins

A twin is a single person, who happens to have been born alongside another. That’s different from Dutch, in which “a twin” refers to the identical twosome.

The Dutch term een tweeling treats the two individual kids as a single group entity, whereas the English a twin is just one of the pair. So your school run would for example be to pick up “the twins”. Not “the twin”.

• My dad and his brother were twins. You could say he had a twin, or that he had a twin brother, but not that they were a twin.
• So if you’re talking about several occurrences, say within a family or for research, you can’t just say “twins.” It has to be e.g. sets of twins
• The constellation or astrological term (Gemini) is also a plural when given the English name: The Twins.

Not sure how common the Dutch approach is in other languages. But it confused the hell out of me the first time I came across it.

Prevalence: low. Not a particularly common topic…
Frequency: very high. …but Dutch people often genuinely don’t realize that the terminology is used differently in other languages!
Native: no. The Dutch usage sounds well wrong.