1. On the lawfulness of change in phonetic inventories Dinnsen, Chin, & Elbert (1992)

2. Purpose of Study Principles/universalsprincipled descriptions of normally of disordered sound developing soundsystems systems n to see how they overlap n are they part of the same system? (delayed) n are they separate? (deviant)

3. 3 parts of the study: n Phonetic inventory –5 characteristic inventory types –implicational laws n phonotactic constraints n compared to normals

4. Importance of Article n Provided a framework for disordered systems using independent analyses –described commonalities of disordered sound systems –disordered sound systems are principled (non-random) –disordered systems similar to normal systems n can identify “delayed” versus “deviant” n provided information on tx options

5. Importance of Article n When you use principles that are formulated in terms of distinctions, rather than in sounds, able to capture commonalities across individuals n There is no specification of the range and limits of variation of the basic properties of a sound system –therefore, we can’t compare to normal systems to see if disordered systems correspond to normal systems

6. Therefore, the purpose of the study was to examine the phonetic inventories in order to establish the range and limits of variation of disordered sound systems

7. Implicational Laws (phonetic inventory) n If you have [lateral] or [strident] distinction --> liquid ([nasal] distinc) LEVEL ELEVEL D n If you have liquid ([nasal] distinction) -->frics OR affr LEVEL D LEVEL C n If you have frics OR affr --> voiced and voiceless obs LEVEL C LEVEL B

8. Implicational Laws (phonetic inventory) n If you have [voice] distinction ->(a) coronal [coronal] distinc among anterior obstruents among anterior obstruents (b) nasal and glides (b) nasal and glides [sonorant] [consonantal] [sonorant] [consonantal] LEVEL BLEVEL A

9. How do Disordered Sound Systems “Fit” with Normally Developing Systems? n Stops, nasals, glides (Level A) acquired before fricatives, affricates, liquids (Level C - E) n anterior sounds (Level A) acquired before nonanterior sounds (Level B) n voice distinction acquired relatively early (Level B)

10. Implications for intervention: If you treat sounds that are phonetically complex (i.e., higher levels), you may not need to treat intermediate levels since they are implied through linguistic principles - they will be acquired on own without direct treatment