Find it, understand it, use it: the ISO standard redefines plain language as a user outcome
Plain language practitioners have long understood that there is more to plain language than readability. Now, a new benchmark from the International Organization for Standardization (ISO) gives you a way to assess whether your communications work for the people they're meant to serve.
For writers and communications professionals across all sectors, the new standard provides nearly universal plain-language principles, guidelines and techniques.
According to the standard, ‘A communication is in plain language if its wording, structure, and design are so clear that the intended readers can easily find what they need, understand what they find, and use that information.’
The definition shifts the focus from mechanical measures such as readability formulas to how successfully readers can use a document. If someone cannot find or understand the information they need, the document has failed - not the reader. As such, plain language communication needs to consider:
what readers want and need to know
their level of interest, expertise and literacy skills
the context in which they use the document
The international plain language standard was developed by a working group comprising 50 plain-language experts, representing 16 countries (including the UK).
Within two years of the publication of Part 1 of the standard in 2023, it was available in 14 languages across 21 countries. This gave plain language something it had long lacked: an agreed international reference point developed through a formal standards process rather than any single organisation's view.
Part 2, published in 2025, is the first international standard to focus on plain-language legal documents and is particularly relevant to terms and conditions. It emphasises that documents must be written for their readers, while maintaining legal precision and accuracy. It gives a process for doing so, and includes design principles such as layering.
Part 4, currently in development, will set out the requirements that organizations must have in place to show they are applying ISO 24495-1:2023 Plain language Part 1: Governing principles and Guidelines. Even if an organisation does not aim for ISO certification, it can use the standard as a guide to apply plain language and build a culture of plain language in their organisation.
Four principles that serve as the basis for plain language
ISO 24495 organises plain language around four governing principles:
Is the communication relevant? Relevance means identifying readers, their purpose and their context, then selecting only content that serves those needs.
Is it findable? Findability means structuring a document so readers can get the information that matches their purpose. Buried information is a design failure.
Is it understandable? This looks at techniques of using familiar words, carefully dealing with technical terms, and using accessible sentence structures.
Is it usable? Usability is the most demanding principle, as it notes that you need to go through research and testing regularly. In a way, this moves plain language from a writing discipline into service design and governance.
The standard is a useful way to get started in plain language and quickly find out about best-practice principles and techniques. To learn more, visit the British Institute website. You can also contact one of the international organisations for plain language, for example, PLAIN.
By Frances Gordon, Director at Narratology
Frances Gordon is the UK Ambassador for PLAIN, the Plain Language Association International, and an expert contributor to the British Standards Institution on the development of plain-language standards. She specialises in clear communication for complex and regulated environments, with a focus on accessibility and financial inclusion. Her work helps organisations make complex information clearer and easier to trust. She is Director of Narratology. See Frances Gordon’s linkedin profile.