cognition language and thought psycholinguistics grammar connotation usa europe linguistic relativity syntax colonialism phonetics slang historical linguistics language learning Sapir-Whorf hypothesis identity politics communication accommodation theory ambiguity accent alphabet sociolinguistics stereotypes communication ancient history ancient greece spain spanish language 20th century ai language language evolution vocabulary language and culture china brain anatomy language history ancient languages french linguistic diversity spanish language change french language conquistadors etymology 19th century ancient rome acoustic phonetics phonology africa italian language latin english language africa colonialism writing systems accents semantics pragmatics american english esperanto german affix cross-cultural communication language and society japanese language accessibility anthropology adult language learning morphology identity loanwords latin language cultural understanding chinese language ancient writing systems americas