Single phenomena are both phonological and phonetic; linguistic phonetic effects like dialect-specific coarticulations and vowel quality differences are documented in this book. There may in fact be a boundary between linguistic and general facts about the sounds of language. This boundary may be called the boundary between linguistic phonetics and general phonetics. This is certainly not the boundary between phonology and phonetics, as commonly understood; it is at a much lower level. Contemporary phonetics straddles the boundary, including both linguistic (language-specific) and more general phenomena. How much of phonetics is contained within linguistics depends on the extent to which phonetic detail is language- or dialect-specific. The details of the location of this boundary within phonetics are empirical matters. But there is no doubt that a useful approach to understanding the limits of linguistics is to learn as much as possible about all aspects of phonetics, whether they turn out in the end to be properly linguistic or non-linguistic (general) facts. Taking the opposite approach -- excluding all of phonetics from linguistics just because some of phonetics is non-linguistic -- is fruitless.