The document discusses theories of first language learning and what they must explain. A theory must explain (1) how children can master their first language quickly despite variability in what they hear, (2) why children learn languages in stages even though the input varies, (3) how children learn the rules of grammar when the input is variable, and (4) why children produce words and sentences they've never heard. Language is variable in that similar ideas can be expressed differently, meanings can have different grammars, and words can have different pronunciations. Children are still able to learn language quickly despite these variabilities.

1. 1
Theories of First Language
Learning
What must a theory of first language learning
explain?

2. 2
What must be explained
• Variability and language mastery
• Variability and stages
• Variability and rules
• Variability and production

3. 3
Variability
• Language is variable in three ways

4. 4
Variability:
Similar ideas / different words
• Similar ideas are expressed by different
words
 Tom always takes the 6:52 train.
 Tom takes the 6:52 train every day.

5. 5
Variability:
Same meaning / different grammar
• The same meaning can be expressed with
different grammatical structures
 I will write my report this weekend.
 I am going to write my report this
weekend.
 I am writing my report this weekend.

6. 6
Variability
Same word / different pronunciation
• Some words are given different
pronunciations
 either: /ēðər/
 either: /īðər/
 People use different dialects

7. 7
Effects of variability
• The effects are increased because
 Children hear many things only once
 What children hear is not always clear
 /wherjyagedat/
• But children still learn it quickly and with
little difficulty

8. 8
Language mastery
• Children say their first words when they
are 12 months
• Children can produce complex sentences
when they are 5 years old.
• First Question: Why can children master
their first language in a short period of
time?

9. 9
Variability and stages of language
learning
• Variability should result in different
sequences
 What each child hears is different so what
they learn should vary from child to child
• Second Question: Why do children learn
languages in stages?

10. 10
Variability and language rules
• Adults make mistakes when speaking
• Children learn correct pronunciation and
correct rules of grammar
• Children don’t know grammar rules, but
know what is grammatical
• Third Question: How do children learn the
rules of language when what they hear is
variable?

11. 11
Variability and production
• Children produce words that they have
never heard.
 sheeps instead of sheep
 comed instead of came
 Fourth Question: Why do children
produce words and sentences that they’ve
never heard?

12. 12
Questions
1. Why do children learn their first
language in a short time?
2. Why do children learn their first
language in stages?
3. How do children learn the rules of their
first language when what is heard is
variable?
4. Why do children produce language that
they have never heard?