Amyotrophic Lateral Sclerosis (ALS): This condition is characterized by progressive muscle weakness, atrophy, and fasciculations, which can lead to swallowing difficulties (dysphagia), speech changes (dysarthria), and limb weakness. The combination of symptoms described, especially the unsteady voice and arm weakness, points towards a motor neuron disease like ALS.

Myasthenia Gravis: An autoimmune disorder that leads to fluctuating muscle weakness, which can affect swallowing, speech, and limb strength. The symptoms can worsen with activity and improve with rest.
Parkinson's Disease: While primarily known for its motor symptoms like tremors, rigidity, and bradykinesia, advanced Parkinson's disease can also cause dysphagia and speech difficulties.
Stroke or Transient Ischemic Attack (TIA): Repeated or single episodes of cerebral ischemia can lead to a variety of symptoms including weakness, swallowing difficulties, and speech changes, depending on the area of the brain affected.

Brainstem Stroke: A stroke in the brainstem can cause rapid onset of severe symptoms including dysphagia, dysarthria, and limb weakness. It is critical to identify and treat promptly.
Meningitis or Encephalitis: Infections of the meninges or brain can present with a wide range of symptoms including weakness, difficulty swallowing, and changes in speech, along with fever, headache, and altered mental status.
Spinal Cord Compression: Compression of the spinal cord, often due to trauma, tumor, or abscess, can lead to progressive weakness, sensory changes, and autonomic dysfunction, including bowel and bladder disturbances.

Kennedy's Disease (Spinal and Bulbar Muscular Atrophy): A rare, inherited disorder that affects motor neurons, leading to progressive muscle weakness and atrophy, including bulbar muscles which can cause dysphagia and dysarthria.
Poliomyelitis: Although rare in areas with widespread vaccination, polio can cause acute flaccid paralysis, which may present with limb weakness and, in severe cases, bulbar involvement leading to swallowing and speech difficulties.
Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can cause a variety of neurological symptoms including dysphagia, dysarthria, and limb weakness, often with rapid progression.