The rapid evolution of the flexibility sector and the increasing adoption of energy-smart appliances and demand-side technologies have heightened the need for clear and accessible communication. However, the widespread use of technical jargon presents a significant barrier to consumer engagement, trust, and participation. This research examines the language used in the energy flexibility sector, analysing 81 documents and identifying 524 unique terms, of which 262 are classified as jargon and 180 as borderline jargon. Market mechanisms and financial terms emerge as the most jargon-heavy subgroups, with 85 and 44 jargon terms, respectively.

While technical language enables efficient communication among industry professionals, it often alienates non-expert stakeholders, including consumers and policymakers. Cognitive processing theories suggest that unfamiliar terminology increases mental effort, discouraging engagement and reducing trust in new energy initiatives. Furthermore, the study identifies a multiplicity of terminology use, where similar concepts are described using different terms across stakeholders, creating further confusion.

By contrast, consumer-focused terms exhibit lower levels of jargon, yet branded terminology used by different providers introduces additional complexity. Programs such as "Saving Sessions," "Beat the Peak," and "KrakenFlex" serve similar purposes but lack standardised definitions, making it harder for consumers to compare and understand offerings.

To address these issues, the study recommends the development of a standardised glossary, simplification of consumer-facing language, and sector-wide adoption of common terminology. Additionally, providing contextual explanations and collaborating with consumer advocacy groups can enhance accessibility and engagement. As a next step, further research is proposed to test consumer understanding of key terms and validate the impact of jargon on participation in energy flexibility programs.