Since the dawn of humanity, people have wanted to communicate with each other. Language was a means to express their thoughts, beliefs and feelings. Now these languages differ from one speech community to another, but a number of circumstances bring them to be used in the same place and time. The branch which is specialised in the study of the causes and effects of contact situations is called contact linguistics. Today, the Algerian speakers use different languages in their life namely: Classical Arabic, Algerian Arabic, Berber and French. Due to the contact between the above mentioned languages, the Algerian society is nowadays known by its sociolinguistic diversity. This diversity gives birth to many linguistic outcomes such as code switching, code mixing, bilingualism, diglossia and borrowing. All these phenomena will be defined and examined briefly in this work. In addition, this book will scrutinize the speech behaviour of the older generations in Tiaret. It will also shed some light on the different language attitudes and the non-linguistic variables that may play an important role in language choice.