TERMINOLOGY LANGUAGE CHANGE

PEJORATION
When  words increasingly acquire negative meanings; gay now means homosexual, opposed to happy.

DIALECT LEVELLING
The belief that language is becoming standardized - decrease in dialect differences.

PRESCRIPTIVISM
The study of language with the intention of controlling it - by dictating rules of usage. Samuel Johnson published the first dictionary in 1755.
  
JARGON
Technical language or highly field-specific vocabulary.

AMELIORATION
A process in which words become more socially acceptable e.g. spastic, pretty.

ETYMOLOGICAL FALLACY
The mistaken belief that earliest historical meaning of a word is it's only true meaning. The word hound originally simply meant "dog" in general. This usage is now archaic or poetic only, and hound now almost exclusively refers to dogs bred for hunting in particular.

'The Great Vowel Shift'
Caused the phonological changes in pronouncing lexis like team to time.

BIDLIALECTALISM
The ability to use two dialects of the same language.

PRINTING PRESS
Intorduced by William Caxton in 1476


ACCOMODATION THEORY (Howard Giles)
 suggests people adjust their body language and accent/speech according to the person they are addressing.

SAPIR WHORF HYPOTHESIS
The idea that language controls or determines the way we think; "A hypothesis holding that the structure of a language affects the perceptions of reality of its speakers and thus influences their thought patterns and worldviews."