Recommendations
1. Use respectful terms for disability, mental health and dying.
2. Avoid referencing age unless it's absolutely relevant.
3. Avoid referencing gender unless it's absolutely relevant.
4. Avoid referencing medical, mental or cognitive condition unless it’s absolutely relevant.
5. Avoid referencing heritage and nationality unless it's absolutely relevant.
6. Use “inclusive” or “accessible” to describe things designed to provide a more equal experience.
1. Use respectful terms for disability, mental health and dying.
Words that are OK and not OK to use vary. Disability can be a very personal matter, as can mental health. As ever, do user testing. Check with the people or person you are writing for or about.
Use positive, enabling language. Do not present people who deal with physical, mental and emotional challenges as victims.
General
“has” or “was diagnosed with” not “suffers from”
“challenge of” not “struggle with”
“support” not “help”
“taken to hospital” never “hospitalised” or “rushed to hospital”
Physical health
“someone with albinism” or “someone who has albinism” not “an albino”
“autism” not “ASD” or “Autism Spectrum Disorder”
“someone who has Alzheimer's disease” or “a person who has Alzheimer's”
“someone with Asperger syndrome”
“attention deficit hyperactivity disorder” or “ADHD”
“blind person” or “blind people” never “the blind"
“someone with sight loss” and “someone with low vision” are OK for people who are partially-sighted
“deaf person” or “deaf people” never “the deaf”
“hearing aid” never “deaf aid”
“disabled people” or “disabled person” not “people with disabilities” or “person with a disability”, never “a cripple”
“Cerebral Palsy” has both words are capitalised
“someone with diabetes” not “a diabetic”
“someone with Down's syndrome” never “someone with Down's”
“dwarf” or “person with dwarfism” but check with the person, never “midget” or "little person”
“person with an illness” or “patient” not “invalid”
“invisible impairment” not “hidden impairment”
“motor neurone disease (MND)”, lower case, never “Motor Neurone Disease” or “Motor Neurone”
“non-disabled people” not “able-bodied people”, “normal people” or “healthy people”
“Tourette syndrome” and “Tourette"s” are both fine
“wheelchair user” not “wheelchair-bound” or “in a wheelchair”
Mental health
“someone with mental health difficulties” never “mad person”, "mental person", "schizo", "nutter", "lunatic", "headcase" or "psychotic person”
“bipolar disorder” never manic depression
Dying
“assisted dying” not “assisted suicide”
“took their own life” not “committed suicide”
2. Avoid referencing age unless it's absolutely relevant.
It's usually unnecessary to refer to people using age-related descriptors like “young” or “old”. Think about it first.
If you do, use:
“older people” never “the elderly”
“younger people” not “the young” or “millennials”
3. Avoid referencing gender unless it's absolutely relevant.
Do you even need to say what gender a person is?
Forms
Do not make gender a compulsory field on forms.
Professions
Use neutral, non-gendered terms for professions. Avoid patronising language.
Examples:
“businessperson” not “businessman, businesswoman”
“firefighter” not “fireman, firewoman”
“police officer” not “policeman, policewoman”
“actor” not “actor, actress”
“chair” not “chairman, chairwoman”
“people” “guys”
“women” not “girls” or “ladies”
Pronouns
If you know someone identifies as male or female, use ‘she’, ‘her’ or ‘he’, ‘his’. Otherwise use ‘they’, ‘their’. When in doubt use their name, or if you're in contact ask them.
Example:
“someone in a red coat walking their labrador” not “a man in a red coat walking his labrador”
4. Avoid referencing medical, mental or cognitive conditions unless it’s absolutely relevant.
Would you say "who has had perfect health since birth"? Probably not. So why reference it if they have not?
Example:
“Tom Brown won the prize for best tomatoes.” not “Tom Brown, a wheelchair user since age 7, won the prize for best tomatoes.”
5. Avoid referencing heritage and nationality unless it's absolutely relevant.
Do you need to say what race a person is?
If you do, be specific and accurate. Do not generalise a person's ethic origins.
Some people may not mind being referred to as for example, "European". Others dislike their ethnic background or culture being described generically by land mass, for example "South American", "Asian food", "she is from Africa" not "she is from Zimbawe".
Especially avoid generalisms if they a have negative connotation.
6. Use “inclusive” or “accessible” to describe things designed to provide a more equal experience.
Use the word “inclusive” or “accessible” to describe design, products, services and places designed to provide a more equal experience to everyone.
For design of a product or service everyone can use we prefer “inclusive” to “accessible”. Inclusive suggests bringing everyone together, whereas accessible keeps people with particular access needs separate. Inclusive design is design for everyone, which we all benefit from.
Examples:
“accessible parking space” not “disabled parking space”
“this service is inclusively designed” not “this service is accessibly designed”
Usability evidence
'Disability is not a dirty word: Moving away from "special needs"', 2018
'The social model of disability', Scope, 2018
GOV.UK Inclusive language: words to use and avoid when writing about disability, 2018
US government on inclusive language, 2017
'A disability is a mismatch between a person’s abilities and their environment', 2016
'The Conscious Style Guide: How to talk about people with inclusive and tactful language', 2016
Mailchimp style guide, 2015
Mailchimp is a US company. Americans tend to use the term 'people with disabilities' but UK disability charity Scope uses the term 'disabled people' because we subscribe to the social model of disability.
This model of thinking says:
• people don’t ‘have’ a disability (they have an impairment such as Cerebral Palsy or Autism)
• people are disabled by society’s barriers (such as information in an inaccessible format or lack of level access).
The social model of disability was developed by disabled people. It says that disability is caused by the way society is organised, rather than by a person’s impairment or difference. It looks at ways of removing barriers that restrict life choices for disabled people. When barriers are removed, disabled people can be independent and equal in society, with choice and control over their own lives.
[https://www.scope.org.uk/about-us/our-brand/social-model-of-disability]
I couldn't see anything about the impact on readability in the research (though clearly it has a bearing on how people feel about what you write).
But I did find a little more on inclusive style, which MailChimp appears to have drawn from.
This article summarises the Conscious Style Guide approach, https://zapier.com/blog/communicate-inclusion-and-diversity/, and the guide itself is here: https://consciousstyleguide.com/about/ (though it seems to me to be more an aggregator of links to how representative groups for particular identities prefer to have language used.
The US Government page on inclusive writing is here: https://content-guide.18f.gov/inclusive-language/ - it seems based on the Conscious Style Guide.