The private language argument was introduced by Ludwig Wittengstein in his Philosophical Investigations (1953). For Wittengstein, language is a rule-governed activity and a language in principle unintelligible to anyone but its originating user is impossible, as even the originator would fail to establish meanings for its putative signs. The private language argument is of paramount significance in modern debates about the nature of language and mind and continues to be disputed. Language disorder has been described since the first accounts of Schizophrenia. Multiple studies have reported anomalies at multiple levels of language processing, from lexical and syntactic particularities to the discourse field, as well as structural and functional abnormalities in brain regions that are involved with language perception and processing.

We aim to critically assess the Wittengstein's argument in the light of recent developments in neuroscience of language.

We conclude that in some patients diagnosed with schizophrenia, presenting a significant language impairment, one can infer a dysfunctional process, in which the language becomes progressively more private and the meaning of utterances harder to ascertain in the realm of interpersonal communication. The privatization of language might contribute to the social cognition deficits and the so-called negative symptomatology of these patients.

The authors have not supplied their declaration of competing interest.