Choosing the level and register for a reader
A document's audience determines how technical its explanations should be and what tone and vocabulary will make them understandable. Plain language varies with the reader's knowledge; it does not require the same language for every audience.
Scientific level and register
The required scientific level should be settled before writing and checked through open dialogue with the client. Scientists working on drug development may need molecular information, whereas sales and marketing groups may need a more general scientific explanation of the same concept. Defining a term such as allodynia can let a non-physician discuss it with healthcare professionals without removing the term.
Purpose and audience help determine whether language should be aimed at patients or doctors and whether its register should be technical or more communicative. Tone and voice also need adaptation between lay materials, regulatory documents, medical communications and advertising: formal writing may suit one project and friendly or lay language another.
A broad distinction separates regulatory and medical-communications texts, each for professional or lay readers. These four groups require different styles of plain English; scientific publications follow the same audience-based principles whether treated as medical communications or a separate group.
Explanations matched to knowledge
The audience's background should guide the language and the use and explanation of scientific and clinical terminology. For example, a clinician may understand “Deposition of hydroxy apatite in the intima, irrespective of the presence of atheromatous changes, impacts on vascular compliance and tissue perfusion”. For a lay ethics-committee member, the explanation can instead describe calcium crystals on the inner surface of blood vessels, vessels becoming stiff, hard or blocked, and reduced blood supply to organs.
Known information need not be explained again: dermatologists may not need an introduction telling them that melanoma is a type of skin cancer, and the discussion may begin with the molecule studied instead. Imagining the reader in front of the writer helps test whether each line is needed.
Clear, concise public information need not be patronising; busy readers can appreciate information that is quick to absorb, with more detail available for those who want it. Simplicity should not be confused with lack of sophistication: readers may be intelligent but short of time and faced with many competing messages. Less formality, and sometimes a little silliness, can convey important patient information without intimidation or condescension.
For scientific readers, prose should clarify complex concepts without necessarily simplifying them or losing the nuances that carry scientific meaning. Technical language develops alongside a field's concepts, so simplification can lose precision and specificity; presenting everything at a specialist-journal level, however, can prevent other readers from understanding it.
Expertise and the lay perspective
Medical writers mediate between people creating knowledge and people who need to read about it. Experts can forget how learning their field first felt; doctors who acquire specialised vocabulary may lose the habit of ordinary language with patients. The writer's challenge is to learn the subject without losing the layperson's perspective and vocabulary.
Moving from regulatory or academic writing to lay writing can be difficult, particularly for complex assessments of benefits and risks. The task requires empathy, understanding of lay readers' motivations and awareness of their difficulties in absorbing complex information.
Readability levels and forms of explanation
Lay materials should be produced at several readability levels, with presentation adapted to different audiences. Museums offering audio guides in different languages and at levels for children, teenagers and adults illustrate how varied detail and presentation can increase interest and be worthwhile.
A 2026 plain-language abstract example showed that removing jargon can make the opening sentences easier to read without necessarily reaching a fifth-grade level. Specialists preparing such explanations may spend hours considering whether a phrase is understandable.
A patient explanation of Mirena used the title “Long-Acting Reversible Contraception”, a figure showing the intrauterine system and its placement, and simple text explaining how it worked. This contrasts with expert product information organised into standard sections for indications, dosing, dosage forms and strengths, contraindications and adverse reactions.
Language for professional and public readers
Plain language also benefits busy regulators and scientific readers facing fatigue and heavy reading workloads. It should be matched to their knowledge rather than made artificially elementary: a regulatory assessor can understand scientific information, and familiar abbreviations such as UK and USA need not be expanded. Regulatory prose should remain scientific, factual, unambiguous and easy to read, without unnecessary complexity or jargon intended merely to sound intelligent.
Journals differ in the technical detail their readers need, but specialist readers are usually already familiar with their therapeutic area. Patients reading trial or medicine information, by contrast, may be chiefly interested in relief of illness or symptoms and reduction of serious risks, so the explanation should address their concerns directly in straightforward language.
Language, layout and style should be tailored to the reader's requirements for each document.