Jeffrey Heath 
From Code Switching To Borrowing [PDF ebook] 

First Published in 1990. This title embraces the descriptive, comparative and historical aspects of the language. It also concerns itself with the classical form as well as the modern and contemporary standard forms and their dialects. Moreover, it attempts to study the language in the appropriate regional, social and cultural settings. This series will be of interest not only to students and researchers in Arabic linguistics but also to students and scholars of other disciplines who are looking for information of theoretical, practical or pragmatic interest.