Language development explains how humans learn to understand, produce, and use spoken, signed, or written language. Students need this reference because language growth is a major topic in developmental psychology, cognition, and social behavior. It helps connect infant milestones to brain development, learning, and interaction with caregivers.
The cheat sheet also supports quick review of key theories and age-related patterns.
Key Facts
- Infants usually begin cooing around 2 to 4 months, babbling around 4 to 6 months, and producing first words around 12 months.
- A phoneme is the smallest unit of sound in a language, such as the difference between b and p.
- A morpheme is the smallest unit of meaning in a language, such as dog, dogs, or un-.
- Telegraphic speech usually appears around 18 to 24 months and uses short phrases such as want milk while leaving out less essential words.
- Overgeneralization happens when a child applies a grammar rule too broadly, such as saying goed instead of went.
- The critical period hypothesis states that language is learned most easily during early childhood when the brain is especially flexible.
- Nativist theory argues that humans are biologically prepared for language, while learning theory emphasizes reinforcement, imitation, and practice.
- Interactionist theory explains language development as the combined result of biological readiness, cognitive growth, and social interaction.
Vocabulary
- Phoneme
- A phoneme is the smallest sound unit in a language that can change meaning.
- Morpheme
- A morpheme is the smallest unit of language that carries meaning.
- Babbling
- Babbling is an early stage of speech development when infants repeat speech-like sounds such as ba-ba or da-da.
- Telegraphic Speech
- Telegraphic speech is the early use of short two-word or three-word phrases that communicate meaning without full grammar.
- Overgeneralization
- Overgeneralization is applying a language rule too widely, often producing errors that show the child has learned a pattern.
- Critical Period
- A critical period is a limited developmental window when learning a skill, such as language, may happen most easily.
Common Mistakes to Avoid
- Confusing babbling with first words is wrong because babbling uses speech-like sounds without stable meaning, while first words consistently refer to people, objects, or actions.
- Assuming language develops at the exact same age for every child is wrong because milestones are averages and normal development includes variation.
- Treating overgeneralization as random guessing is wrong because errors like mouses or goed show that a child is actively applying grammar rules.
- Ignoring the role of social interaction is wrong because language development depends not only on brain maturation but also on communication, feedback, and exposure.
- Equating language only with speech is wrong because signed languages have grammar, vocabulary, and developmental milestones like spoken languages.
Practice Questions
- 1 A child is 5 months old and repeatedly says ba-ba-ba without using the sound to mean a specific object. Which language stage does this best represent?
- 2 A toddler is 20 months old and says more juice instead of I want more juice. Which stage of language development is shown?
- 3 A child says foots instead of feet. Identify the language error and explain what it shows about the child’s grammar learning.
- 4 Why do psychologists often compare nativist, learning, and interactionist theories when explaining language development?