The Chahar-Aine (sp?) armor from Oriental Adventures is an armor add-on that can be worn over padded, leather, or chain shirt armor (I might have forgotten one). Similar to Dastana from the same book, they add an additional +1 armor bonus which stacks with the base armor. Although both of these items have listed armor check penalties, they have no listed speeds, and they are not listed as either light or medium armor (they have their own section: Armor Additions, or somesuch).
Dastana require Armor Proficiency (Light) to use them correctly. Chahar-Aine require Armor Proficiency (Medium) to use correctly. There is no mention in the chart or in the item description, however, about reducing a character's speed.
Does wearing this item with a chain shirt reduce a character's speed?