We propose that the representativeness of a corpus directly depends on its suitability for a specific research goal (including the domain and the linguistic feature(s) of interest). Creating a new corpus involves establishing linguistic research question(s), addressing domain considerations, including describing the domain, operationalizing the domain, evaluating the operational domain (relative to the full domain), designing the corpus, and evaluating the corpus (relative to the operational domain), addressing distribution considerations, including defining a linguistic variable and evaluating the required sample size, collecting the corpus, and documenting and reporting corpus design and representativeness. The steps for evaluating an existing corpus are similar: establishing linguistic research question(s), identifying and acquire the corpus and its documentation, addressing domain considerations, including describing the domain and evaluating the operational domain relative to the full domain, and the corpus relative to the operational domain, addressing distribution considerations, including defining a linguistic variable and evaluating the required sample size, and documenting and reporting corpus design and representativeness. We conclude the book by arguing that corpus representativeness is important for both corpus designers/builders, and corpus researchers who need to evaluate whether a corpus is appropriate for their research goals.

Chapter 9 focuses on the variation found within a language or a speech community, which is at the core of sociolinguistics. In this respect, it differs from chapters that focus on structure and the regularities and invariable properties of language. Basic concepts such as linguistic variables and variants are described and illustrated through examples related to the lexicon, phonology, and syntax. Readers learn about the possible constraints, some of which are structural, that limit the possibility of variation. The chapter then explores the difference between standard and non-standard speech varieties and to recognize that the difference between the two often is not based on any linguistic properties but rather on societal attitudes. It considers social factors that may determine the use of variants, including region, socioeconomic status gender and age. The chapter also examines individual factors such a register. It examines the roles of language planning in different societies. Finally, it focuses on the variation found in bilinguals, including code switching, and the emerging languages such as pidgins and creoles.