Language attrition is the process of decay that a language experiences for lack of use. Attrition may take place at the level of an individual speaker who gradually forgets a language that they used to speak, or at the level of the
speech community that gradually
shifts to another language and change aspects of their original language in that process. Individual speakers whose competency in a language has been affected by attrition may be called
semi-speakers, and languages with high rates of semi-speakers have been shown to undergo similar types of
language change such as loss of grammatical and phonological complexity and irregularity.