Researchers at the Medical University of South Carolina are studying speech and language in people with Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA), and in healthy adult volunteers. These conditions can change how a person speaks and uses language, and the changes may differ from one condition to another. The study uses a tablet-based set of short speech and language tasks, called SLANG, together with computer software that measures features of the recorded speech, such as pitch, timing, and word choice. Participants also complete standard speech, language, and thinking tests and a brief exam by a neurologist, which researchers compare against the tablet measurements. The purpose of this study is to gather early research data: to build a database of these measurements across the groups, to check whether the tablet captures them reliably, and to explore whether they differ between conditions. SLANG is not used to diagnose participants or to guide their medical care in this study. The long-term goal of this research is to develop a tool that could someday help clinicians recognize and tell these conditions apart earlier, but testing such a tool for diagnosis is beyond the scope of the current study.