Understanding Generalization Mistakes in First Language Acquisition

When children learn their first language, they go through several stages. During these stages, they sometimes make mistakes as they try to figure out the rules and meanings of words. Two common types of mistakes are related to generalization: overgeneralization and undergeneralization.

• Overgeneralization: This happens when a child uses a word too broadly. For example, using the word "doggy" for all four-legged animals like cats, cows, and sheep, not just dogs. This shows they have generalized the concept of "doggy" too much.
• Undergeneralization: This is the opposite. A child might use a word too narrowly. For instance, using the word "doggy" only for their family's dog and not for any other dog they see. They haven't generalized the concept enough.

These types of generalization errors are most noticeable during specific stages of language development. Let's look at the common stages:

• Babbling (Mumble): This is an early stage (around 6-8 months) where infants make various sounds. It's about sound production, not typically about using specific words with meanings, so generalization mistakes in word usage don't occur here.
• One-word step (Holophrastic Stage): This stage usually occurs around 12-18 months. Children start using single words to represent whole ideas or sentences (e.g., "Milk!" meaning "I want milk."). It is during this stage that children begin to attach meanings to words, and this is precisely when overextension and underextension of word meanings are frequently observed. They are testing the boundaries of what a word refers to.
• Two-word step (Telegraphic Speech): Around 18-24 months, children start combining two words (e.g., "daddy go", "more juice"). While grammatical overgeneralization (like adding "-ed" to irregular verbs, e.g., "goed") becomes more common later during this stage and beyond, the initial semantic generalization errors (overextension/underextension of meaning) related to individual words are characteristic of the preceding one-word stage.

Based on the typical patterns of child language development, mistakes stemming from overgeneralization and undergeneralization of word meanings are particularly evident during the one-word step stage as children begin to acquire and use their first words.