Idiolect

An idiolect, from Greek idios ‘own, distinct’ + -lect as in dialect, is the language or speech pattern of one individual at a particular period of life.

The idea of individualistic, personal, or private languages has been discussed by philosophers such as Wittgenstein, and linguists such as Chomsky.

Another definition of ‘idiolect’ is that of a "person's incomplete or erroneous grasp of their language, where this latter is inherently social."

By way of example, this relatively well-educated teflpedia editor, brought up in a posh part of South West London in the 1960s, was unaware of the "brought" forms of the verb "bring" until coming across a list of irregular verbs - for EFL students - during his teacher training... His idiolect had the non-standard usage: bring, brang, brung.