ملخص الدراسة:

Linguistic sounds are studied by two branches: phonetics and phonology. The orientalists have studied Arabic phonemes and their phonetic variance like slanting or intensification in the field of phonetics because they are pronunciational changes that do not alter the meaning of the word in Arabic. Most orientalists see the historical transformations of sounds (unconditional) are from phonetics whereas other orientalists, while others view it as being part of phonology. The orientalists paid great attention to the study of the structural changes of sounds (conditional) like assimilation, and substitution and other phenomena which are subjected to the phonetic laws that enter in phonology.