This study is concerned mainly with the nature and social functions of code-switching between Setswana and English. In Botswana, Setswana and English are utilised in conversations between speakers, resulting in the phenomenon of code-switching. Setswana is the primary language of the majority of the people in Botswana and is regarded as the national language, while English is used as the official language. The motive for the selection of English is based on the notion that this language plays an important role in social, economic and political spheres in the country. The fundamental assumption in this study is that code-switching exists as a result of social interaction and language contact amongst speakers with various linguistic repertoires. The study aims to investigate the nature and social functions of code-switching in Setswana in Botswana, especially in the areas surrounding Gaborone City. From a syntactic point of view, the study attempts to determine whether the phenomenon is random and meaningless, while from a functional perspective, it examines the reasons why bilingual speakers engage in code-switching when they interact with other bilinguals, with whom they share the same linguistic repertoire. The study is divided into five chapters. The first chapter comprises the introductory section, which includes the background, motivation, aims and statement of the problem, as well as the organisation of the study. The second chapter provides the theoretical framework of the study and includes the definition of key terms. Chapter Three explains how data was collected and includes transcripts of the speakers' conversations. The analysis, description and discussion of the data are dealt with in Chapter Four. Chapter Five provides a summary of the findings as well as the conclusion and recommendations for future studies. The problem was investigated around Gaborone City in various settings such as a church, a public bar, the National sports Stadium, the media (Radio Botswana), a furniture shop and a taxi rank. The speakers' interactions were recorded and unstructured interviews were conducted at a later stage. The speakers included people from all groups, that is gender, age and various degrees of education. The recorded conversations have been transcribed and analysed. The results have been used to gain a better understanding of the nature and social functions of code-switching. The analysis also looks at the grammatical and syntactic features of switched phrases, clauses and sentences, as well as whether the switching violates any grammatical or syntactic rules of either the host or the guest language. The switches made by the speakers also determine the social functions of code-switching in Botswana. The results show that the phenomenon is common in Gaborone City, as all the recorded speakers tend to indulge in this activity regardless of their level of education. It has been observed that, in general, the less educated people's conversations contain borrowed English words, while the conversations of the better educated sector contain larger stretches of code¬-switching in phrases and sentences. The results reveal that no violation of the grammatical structures of either language occurs during code¬-switching. It has also been found that the phenomenon occurs in all the formal and informal settings mentioned above. In a functional sense, it has been observed that Batswana switch from Setswana to English for various communicative purposes, such as an indication of level of education, a signal of authority and annoyance and to show the powerful and less powerful languages. Other reasons for the switching include the topic/subject of discussion, emphasising a particular point and the signalling of socio-economic status and prestige. The importance of these findings is that it invalidates the fears that some Batswana have with regards to code-switching in Setswana. Additionally, the research sheds new light on the importance of this phenomenon in Botswana. One of the conclusions that can be drawn from the results is that the application of code-switching strengthens and enriches the Setswana language with the new vocabulary. It is a communicative strategy used by bilingual communities in their conversations and instances such as those described above. / Dissertation (MA (Setswana): Sociolinguistics)--University of Pretoria, 2006. / African Languages / unrestricted