Language

1. variable

1.1. because of grammar

1.1.1. grammatical rules that apply to all languages

2. Chomsky

2.1. 1950's

2.1.1. UNIVERSAL GRAMMAR

2.1.1.1. are these grammar rules universal to all languages?

2.1.1.1.1. generative syntax

2.1.1.2. are these rules hard wired in the brain?

2.1.1.2.1. profound & revolutionary impact

2.2. 1980's

2.2.1. NEW HYPOTHESIS OF PRINCIPLES & PARAMETERS

2.2.1.1. All languages:

2.2.1.1.1. share certain grammatical principles

2.2.1.1.2. could vary in the parameters or application of these principles

2.2.1.2. still didn't answer which principles were universal

2.3. 2000's

2.3.1. RECURSION

2.3.1.1. structures can be nested inside each other

2.3.1.2. it can take many forms

2.3.1.3. but not all languages had this principle