Past Tense of “begin”
The past tense of begin is began; the past participle is begun.
Why “begin” behaves this way
"Begin" descends from Old English "beginnan," a strong verb belonging to the same broad ablaut class as "sing/sang/sung," "ring/rang/rung," and "swim/swam/swum" — all of which share the identical i-to-a-to-u vowel pattern across base, past, and participle, one of the most recognizable and internally consistent groups among English's irregular verbs.
"Beginnan" was itself a prefixed compound in Old English, built on a simpler verb "ginnan" (also meaning "to begin") that has since vanished from the language entirely, leaving "begin" as the only survivor of that particular root — a common historical pattern where a prefixed compound outlives its own unprefixed base verb.
The common confusion
The common real error with "begin" is mixing up began and begun — using "begun" as a simple past ("I begun my homework") or "began" after a helping verb ("I have began") — which happens because both forms are unfamiliar-sounding on their own, unlike more everyday verbs where the correct form feels obvious by habit.
How it's actually used
"Begin" and "start" are near-synonyms in most contexts, but "begin" tends toward a more formal register (typical of written or careful spoken English) while "start" dominates casual speech — a stylistic distinction rather than a grammatical one, similar to the difference in register between "purchase" and "buy," and one reason "begin" shows up disproportionately often in formal writing and business English compared to conversation. "Begin" pairs naturally with an infinitive ("begin to understand") or a gerund ("begin understanding") with almost no difference in meaning between the two — a rare flexibility shared with "start" and "continue" but not with most other verbs, which strictly require one complement pattern or the other.
Across the tense system
"Begun" pairs with "once" in the fixed narrative-transition phrase "once begun," and with "no sooner" in the literary construction "no sooner had it begun than...", both slightly formal constructions that showcase the participle in a register more common in written narrative than everyday conversation.
Common real mistakes
Using "begun" as a plain simple past ("I begun my homework") instead of "began" is a common nonstandard error, alongside the reverse mistake of pairing "began" with a helping verb ("I have began") instead of the correct participle "begun." A further genuine point of confusion is "begin" versus "start," which are close synonyms but differ slightly in collocation: English says "begin a sentence with," "begin to understand," and "the beginning of the book," preferring "begin" in these fixed academic and literary phrasings, while "start a car," "start a business," and "start over" strongly prefer "start" instead — a distinction governed by convention rather than any rule, and one native speakers absorb without ever being taught it explicitly. A further genuine error is treating "begin" as requiring only the infinitive form, when in fact both "begin to rain" and "begin raining" are equally correct, a flexibility many learners aren't taught explicitly and so avoid the gerund form unnecessarily out of caution.
Examples
- She began her career as a teacher.
- They have begun renovating the house.
- He begins work at seven every morning.
- We had already begun eating when they arrived.
- It would have begun raining any minute.
- Has the meeting begun yet?
- Let's begin with the basics.
- The show is beginning in five minutes.
Memory trick
Group "begin" with "sing," "ring," and "swim" — all four follow the exact same i/a/u pattern (sang/sung, rang/rung, swam/swum), so if you're unsure whether it's "began" or "begun," check which slot the sentence needs the way you would with "sang" vs. "sung." Remember "begin" tolerates both an infinitive and a gerund equally well ("begin to rain" or "begin raining"), one of the few English verbs flexible enough to take either complement without changing its meaning — a genuine exception worth knowing rather than defaulting only to the infinitive out of habit, since native speakers use both constructions constantly and interchangeably in ordinary conversation and writing alike. A related fixed phrase, "to begin with," introduces a first point in a list or argument, a discourse-marking use distinct from every literal sense of starting something.