When mental health clinicians perform mental status examinations, they examine the language patterns of patients because abnormal language patterns, sometimes referred to as language dysfluency, may indicate a thought disorder. Performing such examinations with deaf patients is a far more complex task, especially with traditionally underserved deaf people who have severe language deficits in their best language or communication modality. Many deaf patients suffer language deprivation due to late and inadequate exposure to ASL. They are also language dysfluent, but the language dysfluency is usually not due to mental illness. Others are language dysfluent due to brain disorders such as aphasia. This paper examines difficulties in performing a mental status examination with deaf patients. Issues involved in evaluating for hallucinations, delusions, and disorganized thinking are reviewed. Guidelines are drawn for differential diagnosis of language dysfluency related to thought disorder vs. language dysfluency related to language deprivation.