AP® Psychology review sheet from Aim for Five (aimforfive.com/psych/units/3/3-5)
Unit 3 · Topic 3.5
3.5 Communication and Language Development
Language is a shared system of symbols, built from phonemes and morphemes and governed by rules of grammar and syntax, that lets you create an endless number of new sentences. Children in every culture communicate with gestures and pass through the same stages, from cooing and babbling to single words and short telegraphic phrases. Along the way they make predictable errors such as overgeneralizing grammar rules.
Key terms
- phoneme
- morpheme
- syntax
- babbling
- telegraphic speech
- overgeneralization
What makes something a language
Language is a system of symbols that a group of people agrees on. The symbols are arbitrary: there's nothing about the sound 'dog' that resembles a dog, which is why other languages use completely different words. Language is also rule-governed, meaning words combine according to rules, and generative, meaning you can use a limited set of words and rules to create sentences no one has ever said before.
You won't be tested on pragmatics, the social rules of how language is used in conversation.
The building blocks
Every language is built from the same kinds of units and rules.
- Phoneme: the smallest unit of sound in a language. The word 'chat' has three phonemes: ch, a, t. Languages use different sets of phonemes.
- Morpheme: the smallest unit that carries meaning. It can be a whole word ('cat') or part of one: 'unbreakable' has three morphemes (un, break, able), and 'cats' has two (cat, s).
- Semantics: the rules for deriving meaning from words and sentences. The ending '-ed' means something happened in the past.
- Grammar: the full system of rules that lets people communicate and understand each other.
- Syntax: the rules for ordering words into sentences. In English, 'The dog chased the cat' and 'The cat chased the dog' use the same words with different meanings because of word order.
How language develops
Before speaking, babies communicate with nonverbal gestures, like pointing at something they want, and children in all cultures do this. Formal language then develops through a series of stages that appear in the same order across cultures, although exact ages vary.
| Stage | Typical age | What it looks like |
|---|---|---|
| Cooing | About 2 months | Soft vowel sounds like 'ooo' and 'aah' |
| Babbling | About 4 to 6 months | Repeated consonant-vowel sounds like 'ba-ba-ba'; over the next months, babbling narrows toward the sounds of the home language |
| One-word stage | About 12 months | Single words that often stand for a whole idea, like 'up' meaning 'pick me up' |
| Telegraphic speech | About 18 to 24 months | Two-word or short phrases mostly made of nouns and verbs, like 'want cookie' or 'daddy go' |
Overgeneralization and what it shows
After the telegraphic stage, children's sentences quickly grow longer and more complex. As they learn grammar rules, they often apply them too broadly. This is overgeneralization (also called overregularization): saying 'I goed' instead of 'I went,' or 'two mouses' instead of 'two mice.'
These errors are actually a sign of progress. Adults don't say 'goed,' so children aren't simply copying what they hear. They have figured out a rule (add '-ed' for past tense) and are applying it on their own. The same pattern shows up in people learning a second language.
Language development also connects to critical and sensitive periods (3.2): children exposed to language early learn its grammar much more easily than those exposed later. And language depends on brain areas such as Broca's and Wernicke's areas (1.4).
Worked examples
Try each one yourself first, then open the solution.
- Example 1
Counting phonemes and morphemes
How many morphemes are in the word 'replayed'? How many phonemes are in the word 'ship'?
Show the solutionHide the solution
- Step 1: Break 'replayed' into units of meaning: 're' (again), 'play' (the action) and 'ed' (past tense). That's three morphemes.
- Step 2: Break 'ship' into sounds, not letters: sh, i, p. The letters 's' and 'h' together make one sound, so that's three phonemes.
- Step 3: The trap is counting letters. Phonemes are sounds, and 'ship' has four letters but three sounds.
Answer: 'Replayed' has 3 morphemes; 'ship' has 3 phonemes.
- Example 2
Identifying the stage
A toddler points at the door and says, 'Mommy go car.' Later she says, 'I runned fast!' Identify the stage and the error.
Show the solutionHide the solution
- Step 1: 'Mommy go car' is a short phrase made of key nouns and a verb, leaving out small words like 'is' and 'to.' That is telegraphic speech.
- Step 2: 'Runned' applies the regular past tense rule to an irregular verb. That is overgeneralization.
- Step 3: Pointing at the door is a nonverbal gesture that supports her words.
Answer: Telegraphic speech, followed by an overgeneralization error ('runned').
Common mistakes
- Counting letters instead of sounds for phonemes. 'Ship' has three phonemes because 'sh' is one sound.
- Swapping phonemes and morphemes. Phonemes are units of sound; morphemes are units of meaning.
- Treating overgeneralization as a sign of delay. It shows a child has learned a grammar rule, even if they apply it too widely.
- Mixing up syntax and semantics. Syntax is word order; semantics is meaning.
On the exam
- Expect scenarios asking you to identify a stage (cooing, babbling, one-word, telegraphic) or an error such as overgeneralization.
- Language research often involves infants, so be ready to name ethical safeguards like parental consent and protection from harm.
Connected topics
Videos
Check yourself
5 questions on 3.5 Communication and Language Development. Pick an answer to see if you got it, and why.
A 3-year-old who used to say "I went" and "two mice" now says "I goed to the park" and "I saw two mouses." Which statement best explains this change?
How many morphemes are in the word "unbreakable"?
A 2-year-old says "Daddy go car" and "more juice," leaving out small words like "the" and "is" but keeping the words in a sensible order. This child is using
Researchers played pairs of speech sounds to infants from English-speaking homes. Some pairs are treated as different sounds in English, while other pairs are treated as different sounds only in Hindi. An infant who noticed a change between the two sounds in a pair would turn toward a toy display.
At 6 to 8 months, most infants noticed the change for both English and Hindi pairs. At 10 to 12 months, most still noticed the change for English pairs, but few noticed it for Hindi pairs.
Hypothetical experiment
The speech sounds in this study are best described as
Which conclusion is best supported by the results?
0 of 5 answered