Synesthesia

Synesthesia is a neurological condition of mixed sensory perceptions. Where one sensory pathway is stimulated, it is automatically processed across additional sensory pathways, invoking an overlap of sensory experiences. For instance, synesthetes often perceive letters and numbers to have a specific color or texture, an alphabet unique to each individual. While this condition does not hinder the individuals, their perceptual experiences are significantly different from the general population, as indicated in the video below.