A word, usage, or pronunciation not used by educated speakers is nonstandard English.
Examples of nonstandard English include informal expressions, those that are not taught at academies or used in business/legal communication.
Nonstandard English is commonly used between friends, family or within a specific age or population group. However, it will not be used by educated speakers most of the time, as they will be inclined to use accepted, standard English when the context requires it.