Alpine refrains are a type of traditional singing style originating from the Alps region of Europe. They are characterized by a yodeling sound, which is created by alternating between two different notes. The term 'YODEL' (5 letters) is used to describe this vocal technique, while 'yodels' (6 letters) is the plural form of the word. Another term for Alpine refrains is 'tralas' (6 letters), which is derived from the French word for YODEL.