walloon: a dialect of French spoken in Belgium and adjacent parts of France
indo-european: the family of languages that by 1000 BC were spoken throughout Europe and in parts of southwestern and southern Asia
mucus: protective secretion of the mucus membranes; in the gut it lubricates the passage of food and protects the epithelial cells; in the nose and throat and lungs it can make it difficult for bacteria to penetrate the body through the epithelium