When is used to ask or talk about the time that something happens or happened.
“When” comes from Old English “hwænne,” from Proto-Germanic “hwan,” a time-question word. It is part of the same ancient “wh-” family as “what,” “where,” and “why.”
With one syllable, “when” lets you jump along a timeline—past, present, or future—without naming any clock time. It shows how language lets us treat time almost like a place we can point at.
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