ABSTRACT
The phonologies of different languages are in many respects very similar, to the extent that some features appear to be part of every language. The fact that languages shows so many similarities in their sound structures cannot be accidental. Different perspectives have been taken on this fact. This chapter shows that the segment inventories of languages tend to be constructed as if languages drew on the stock of phonological resources by adding elements to sets of segments. It uncertains of the extent to which phonologists believe that certain segments or particular distinctive features are innate, but our guess is that most would maintain that it is contrastiveness which is innate, but that the way contrasts get spelled out in features may not be. Low-cost contrasts are thus frequent. Some sound contrasts are so easy to make and so clear to the ear that they are found in every language that has been described.
