An area of language instruction that developed significantly as a result of Krashen’s theory of acquisition and comprehensible input is the teaching of vocabulary. Historically, vocabulary in textbooks was presented in lists of words in the target language followed by their native language equivalents, as in the following list related to the destruction and conservation of the environment:
la contaminación pollution
el desperdicio waste
desarrollar to develop
construir to construct
los recursos naturales natural resources
proteger to protect
reciclar to recycle