5. Language development ‘milestones’

• Chronology of Language Development: Birth – 2 years

  
• Stages of language acquisition: semantic development

  Children’s understanding of language develops at a different rate than their production of language

  • By 18 months, children typically understand the meaning of 50 to 100 words.
  • By 24 months, children typically understand the meaning of about 900 words.
  • By 6 years old, children typically know around 8000 words.
• Learning the names for things

  • Children learn new words rapidly, on the basis of very little information: the riddle of reference
  • For example, how do they know that ‘rabbit’ refers to the whole creature, and not a particular part of the rabbit. The action the rabbit is making, or all furry creature?
• Word learning constraints

  Expectations about what the word is likely to refer to:

  • Perceptual constraints → word learning based on attention to perceptual similarity of objects.
  • Conceptual/whole object constraints → assumption that a new word refers the entire objects.
  • Social constraints → Word learning based on social cues from another person (e.g., joint attention and pointing)
• Stages of language production: pre-verbal communication

  From birth to around 10 months Early vocalizations – e.g., Cooing, crying, babbling Babbling develops…

  • Practice producing phonemes, pitch, and rhythm of native language
  • Gradually links phonemes to morphemes
  • Deaf babies babble, but do so with their hands if exposed to sign language.
• Stages of language production: one- and two-word utterances

  One-word utterances emerge at around 12 months

  • E.g., mummy, daddy, cat
  • First words that have meaning
  • Holophrases → a single word is used to stand in for a larger sentence

  Two-word utterances emerge around 18 months

  • Move to telegraphic speech → Children only using crucial words still to stand in for sentence, but tend to be consistently formed and worded
• Semantic development: Errors in word use

  • Overextension = Children use a single word to refer to many things, which is incorrect because its is too broad
  • Under-extension = Children use a single word to refer to a specific thing, which is incorrect because it is too specific
• Chronology of Language Development: 2 years+

  
• Stages of language production: Acquiring grammar

  From two years onwards…

  • Children learn how to modify the meanings of the words they use
  • Largely by modifying root words with morphemes. How do we use words and sentences we have not heard before?
  • Below is a list of potential new verbs, which could be used in sentences like:
  • Zainab likes to X

  
• Acquiring Grammar: Productivity of language

  Two different types of learning mechanisms

  1. Rules are learnt via abstraction and generalisation
  2. Learn exceptions to the rules via memory and/or analogical reasoning
• Rules are learnt through abstraction/generalisation

  Rules are abstract and general: they apply to many different word forms

  
• Learn exceptions to the rules via Memory and/or Analogical Reasoning

  • Forms that do not follow rules are stored in the mental lexicon as separate entries. They can only be known if they have been previously encountered.
  • If we encounter a sufficient number of irregular forms that look like each other, we may notice the similarity and use analogical reasoning to guess other similar forms

  
• Productivity and learning (New Language) What did you do?

  
• Stages of language production: Morphological rules


  From two years onwards…

  • Children learn how to modify the meanings of the words they use
  • Largely by modifying root words with morphemes.
  • How do we use words and sentences we have not heard before?