Speech and language disorders, such as concretism and formal thought disorder (FTD) are core symptoms of Schizophrenia, but do occur to a similar extent in other diagnoses such as bipolar disorder and major depression. We will review clinical rating scales of FTD and introduce a new, validated scale, the TALD. Further, structural and functional brain imaging data will be reviewed and own novel findings presented, relating speech and language dysfunctions to neural networks, within schizophrenia and across the “functional psychoses”. The impact of genetic variance and NNDA receptor blockage on brain function will be addressed with a particular focus on speech and language (dys-) function. We demonstrate, from the genetic to the brain structural and functional level, that particular aspects of the neural language system are disrupted in patients with FTD across traditional diagnoses.