Change from below
Change from below is linguistic change that occurs from below the level of consciousness. It is language change that occurs from social, cognitive, or physiological pressures from within the system. This is in opposition to change from above, wherein language change is a result of elements imported from other systems.[1][2]
Change from below first enters the language from below the level of consciousness; that is, speakers are generally unaware of the linguistic change.[2] These linguistic changes enter language primarily through the vernacular and spreads throughout the community without speakers conscious awareness. New linguistic changes that enter the language from below are most commonly used by the interior classes, as displayed by William Labov's curvilinear principle. Change from below is seen in Labov's Philadelphia study, where a series of new vowel changes were most often used by the interior classes.[1][2]