The box breaked, the eraser sinked

Have you ever experienced something from the written page come to life? I have. No, I didn’t see the purple dragon from my teen fantasy novels, or communicate with an unfolded-refolded nine-dimensional sophon from Trisolaris (hey…it’s been forever since my last post, I’m way overdue for a bit of nerding out).

No – I’m talking about something much more on-topic for this blog. A decade ago, I had read research on young children’s acquisition of verbs…of the learning phases they go through, particularly with respect to past tense forms. This last year, I’ve witnessed that phenomenon in real time with my toddler son. It has been incredible to observe his (now veritable flood of) daily speech, while having some idea of what’s happening behind the cerebral scenes.

I’ve been keeping a journal of my son Ryden’s language development (and his language environment in terms of parental input) since his preverbal days – starting when he was about 4 months old. Mining that journal for examples relevant to the subject at hand, I found the below:

(Age is represented by the formatting convention years;months, e.g. 2;5 means “2 years and 5 months”)

I’ve italicized all of the past tense verb forms. Spot the errors?

There are actually only three unique errors (four instances): falled in “I falled”; breaked in “the box breaked”; and sinked in “the eraser sinked”. Correct usage is more frequent: saw, went, ate, hid, drank.

What exactly is happening here?

The verbs above share a common trait – they’re all irregular verbs. Most verbs in English are regular, which, in part, means they have an affixation rule, “add the suffix -ed to form the past tense”. Irregular verbs don’t take this same past tense ­-ed ending; instead, they take more idiosyncratic forms involving stem changes, which must be memorized individually (e.g. find → found; take → took; hold → held).

English-speaking children start marking verbs for past tense between the ages of late-one and three. Initially, they produce some correct irregular past tense forms. Then, they go through a period (between ages 2-5) where they make overregularization errors. As they grow older, the mistakes diminish, and kids conjugate irregulars correctly again.

Overregularization is a phenomenon that covers a range of linguistic/grammatical errors. For the case here, a child applies the regular past -ed suffix to irregular verbs, resulting in incorrect past tense forms (e.g. find → finded; take → taked; hold → holded).

These errors are an indication that the child is generalizing beyond adult talk, and that they’ve acquired a past-tense type of rule. Their brain has unconsciously caught on to the fact that verbs have two alternate forms (jump and jumped), and subsequently wants to apply it to all verbs, whether regular or irregular. [1]

This process – where toddlers first use some accurate forms, then overgeneralize, then use the accurate forms again – is called “U-shaped development” in child psychology.

A few more details on this phenomenon:[2]

• A common explanation is something like the “Blocking-Plus-Retrieval-Failure” Theory
  • The child’s innate grammar contains a “blocking” feature – where memory retrieval of an irregular form blocks the regular -ed rule. Since the child’s memory retrieval is not as strong as an adult’s, it inevitably fails on occasion…whereupon the child applies the regular rule instead
• They may seem prominent, but overregularization errors are actually rather rare – the average rate being ~4% (of all irregular verb instances)
• The more frequently a child hears a parent/adult use a specific irregular verb, the more likely they are to get it right (NOT overregularize) themselves
• Toddlers may use correct and overregularized variants of the same verb within a single speech stream
• These past tense errors occur cross-linguistically – young French-speaking children make them too, for instance
• Last, a fun fact: The top ten most frequent English verbs (according to one Brown University study) are ALL irregular: be, have, do, say, make, go, take, come, see, get.

So next time you hear a three-year-old say something like “it goed away,” after your gut reaction to either cringe or coo, spend a moment appreciating the marvel that is that young human’s linguistic mind.

[1] Pinker, S. (1995). Why the Child Holded the Baby Rabbits: A Case Study in Language Acquisition.

[2] Pinker, S. (1995). Why the Child Holded the Baby Rabbits;

Marcus, G. F., et al. (1992). Overregularization in Language Acquisition; and

Paradis, J., et al. (2007). French-English Bilingual Children’s Acquisition of the Past Tense.