English-speaking children say gooses for geese and knifes for knives. Japanese-speaking children, by the same logic that turns “tabeta” (ate) into a past tense, will sometimes say “neQta” for “neta” (slept). Is this just a slip to be dismissed? Jespersen found, inside these “mistakes,” a strikingly orderly system.
Why does a native language get learned so well?
Jespersen starts from a single question. Learning a foreign language comes with specialist teachers, textbooks, dictionaries, a carefully organized curriculum — and still, a language learned as an adult usually ends up only imperfectly mastered. A native language is the opposite story: no specialist teacher, no system, learned haphazardly by ear — and yet even the most ordinary child ends up speaking it flawlessly. Why the asymmetry?
Collecting the “mistakes”
The clue to the answer is in the mistakes themselves. Look at the examples Jespersen collected.
- gooses (instead of geese), tooths, knifes — irregular plurals rebuilt with the regular -s ending.
- littlest, littler, goodest, baddest — comparatives and superlatives rebuilt on the regular pattern.
- One child, reasoning by analogy from thieves, said chieves for chiefs — an analogy running, this time, in the opposite direction, built from an irregular form.
- A Danish-speaking child would tack a possessive -s onto the end of an entire question, producing something like “Who is that’s?” for “whom does that belong to?”
Not careless — too faithful to the rule
Line these examples up, and a common thread appears. A child isn’t memorizing words one at a time — the child has extracted the rule itself (“plurals take -s,” “superlatives take -est”) and applies it consistently to every word at hand. Irregular forms like geese and knives have to be picked up directly from adult speech and memorized as special cases; a child who hasn’t yet finished learning those exceptions applies the regular rule first — and applies it faithfully. So a child’s “mistake” doesn’t happen because the child doesn’t know the rule. It happens because the child knows the rule too well. Jespersen puts it this way:
…each of us thus now and then really creates something never heard before by us or anybody else.
Summary
| Point | Content |
|---|---|
| The starting question | Why is a native language mastered so completely, without any systematic teaching? |
| The examples collected | gooses, tooths, goodest, chieves, “who is that’s,” and more |
| The regularity found | A child extracts a rule and applies it consistently to every word |
| What the “mistake” really is | Not ignorance of the rule — just not yet having learned the exception |
In a nutshell — a child saying “gooses” isn’t confused. It’s evidence that the power to apply a rule with total, unwavering consistency — a power adults have long since lost sight of — is still alive and working.