Businesses communicate a wide variety of messages to diverse audiences using a number of different communication types and channels daily. For example, business communication includes business reports, documents (booklets, leaflets, and official communiqués), notices, agreements, web copy and advertisements that are produced continually to address a variety of business communication needs for a variety of audiences. Although written business communication has a significant impact on customer satisfaction and consumer attitude which, in turn, affects consumer behaviour positively or negatively, there is a lack of research investigating the knowledge and application of plain language in business communication. Many studies were found to be related to communication and language, however, studies about plain language use were less prevalent. Therefore, this study aimed to investigate the awareness of the plain language regulations stipulated in the South African Consumer Protection Act (CPA) 68 of 2008 (2009). The application of these plain language principles within businesses in the Port Elizabeth Metropole, with specific reference to its use in written business communication was also investigated. The study also aimed to identify plain language best practices and constraints resulting from plain language application or non-application within the selected organisations. The research focused attention on the impact of business communication on customer satisfaction, consumer attitude and, ultimately, consumer behaviour as well as the need for plain language use in written business communication practices to ensure effective and fair (ethical) communication. A comprehensive literature review was conducted on communication, communication theory and consumer behaviour, as well as on plain language principles which might add to the effectiveness of organisations’ written business communication, to provide a theoretical foundation for the study. The study’s research methodology was approached from a phenomenological (descriptive and interpretive), and somewhat positivistic perspective, utilising qualitative and limited quantitative measures to obtain data. For this reason, three managers from three respective organisations within the Port Elizabeth Metropole were interviewed and asked to complete a rating-scale survey to obtain insight on the written business communication practices of these organisations. A content analysis of documents supplied by the participating organisations were also reviewed to provide commentary on the plain language application in each organisation. Furthermore, Section 2 of the South African CPA 68 of 2008 (2009) was also reviewed to measure and comment on the application of plain language in these organisations. Based on the data analysis, it was evident that organisations in the Port Elizabeth Metropole were aware of plain language and the plain language regulations stipulated in the South African CPA 68 of 2008 (2009), but that they were not certain what the regulations entailed exactly. Furthermore, plain language principles were applied in the participating organisations, however, complications and areas for possible improvement were identified in the data. From the study’s findings, various recommendations were made that could assist the organisations to improve their organisations’ plain language application. These recommendations included, for example, appointing plain language champions to monitor plain language application in the organisation, as well as assessing language competence of staff and training them to improve their language competencies. Recommendations for future research suggested that future studies needed to include a larger research sample, a more diverse sample population to include consumers and a broader industrial demographic. In addition, future studies could attempt to investigate communication barriers that inhibit or challenge comprehension in consumer communication.