Many users of the Internet have a variety of individual requirements. People may have sensory disabilities (e.g. they may be totally blind, partially sighted, deaf, or hard of hearing); cognitive (people with dyslexia) or physical impairments. They all have different needs and requirements. It is estimated that 10 - 20% of the European population have a disability.
Older people, people with low literacy, non-native speakers, people with low-bandwidth connections, and people using older technologies can also benefit from accessible websites.
Some users will be aided by assistive technology when they visit your website. Others will have adjusted their browser settings.
Blind people, those with low vision, and those without the ability to view the full range of colours all have visual disabilities. Using the Internet is particularly challenging for this group of users, as a lot of information is presented in a visual format.
Blind people use software called screen readers which reads out web pages in synthetic speech to help them access the Internet.
Partially sighted people may also use screen readers, and in addition adjust the settings on their browsers to increase the text size on your web site, or make the contrast between the text and background stronger.
Web Aim provide a detailed article on visual disabilities where you can find out more about how this category of user browses the web. The Royal National Institute for the blind has a detailed list of common eye conditions and their symptoms.
The main ways in which you can make websites more accessible are:
There are a number of hearing impairments that can affect the use of the Internet. Audio, video and multimedia content is now very commonly found on websites. If this content does not have transcripts or captions, then it is not accessible to those with hearing impairments.
Find out more about the different types of hearing impairment.
The deaf have a very close-knit deaf culture and community. Learn more about deaf culture and tips for making a website more accessible for the deaf.
View a simulation of the effect that deafness has on the experience of multimedia resources(Flash required).
The main ways in which you can make websites more accessible are:
Users with physical impairments may have spinal cord injuries, multiple sclerosis, Parkinson's disease, missing limbs and many other types of disability. They use a wide range of assistive technology including alternative designs of keyboards and mice, head mounted pointing devices and voice recognition software.
Find out more about the different types of physical impairments and their symptoms.
The main ways in which you can make websites more accessible are:
Users with cognitive impairments can feel confused and disorientated on the web. Dyslexia is one of the most common cognitive disabilities.
You can view a simulation of the effects of a cognitive disability to get some understanding of the issues.
Some users with cognitive disabilities will use screen readers, others will change their browser or system settings, and others will not make any changes.
Some commercial tools are available that are occasionally used to read out web pages such as Browsealoudand Read Speaker.
Particular things you can do to improve accessibility for this group of people are:
Read more about these issues in 'Design Considerations for those with Cognitive Disabilities'.
This online guide will help you write concisely, and you can learn about how users read on the web .
Older adults are more likely to have a combination of disabilities which means they may have a variety of requirements (for instance a user may be both hard of hearing and partially sighted). They are likely to be less familiar with technology and therefore simplicity, ease of navigation and help features such as site maps are important.
Content should be clear and simple. This is particularly important for users who do not use the language of the website as their first language, and those with low literacy levels.
Many of the accessibility features you can add to a website will assist users of both old and new technology. For instance adding a textual description of an image will be useful for those who do not display images because of bandwidth issues, those using text only browsers, and those using older mobile phones which cannot display images. Using Web Standards will help ensure that your website is future proof.