The aim of this edited collection is to extend our knowledge of the important phonological concept of sonority to a range of other languages (several of them under-described languages). In previous work, sonority has most often been applied to languages commonly described in the linguistics literature. In this collection we have expanded this to include languages of Africa, Asia, and the Americas, as well as phonological development in lesser reported languages. The challenges to sonority that these studies reveal is discussed in the concluding chapters where alternatives to this concept are explored.