Overview

Screen readers are audio interfaces. Rather than visually display the Web content for users in a "window" on screen, screen readers convert text to speech synthesis, so that users can listen to the content. Sighted people usually have a hard time imagining how it is possible to use only audio interface to browse the web so their access to the world is visual. It is true that the user experience of an audio interface is completely different. Without screen readers, blind people would need other people to read aloud the content for them. The technology allows independent access to information for people who otherwise would still need the support and assistance of others.

Screen readers do not read web content just like humans do. The voice may sound a little robotic and monotonous. In addition, experienced users often accelerate the speed of speech to a reading rate of 300 words per minute or more, which is too fast for an inexperienced listener can understand. Indeed, when people listen to a screen reader for the first time in a normal reading of about 180 words per minute, they are already complaining that he reads too quickly. It takes time to get used to listening to a screen reader, but the interesting thing is that once users get used, they can read the contents at a speed that may surprise sighted people.

et Window Eyes de GW Micro. Two screen readers are the most common JAWS from Freedom Scientific and GW Micro Window Eyes. This software can not only read Web content, but also the functionality of the Windows operating system, software for word processing and other software.

Linearization of contents

Audio interfaces read the contents of users linearly, one after the other object. This contrasts with the way most people use visual interfaces. Sighted users can analyze an entire screen almost instantly understand the presentation, the art style and other aspects of the macro content. Users of screen readers can not understand these macro as fast. The linear progression of content playback from the beginning to the end of the web page is like a menu of automated phone systems, which do not reveal all options at once. Users must move through these systems a graduated manner. The idea that the audio interfaces are linearized so the Web content is an important element that should guide Web developers during the engineering and development of websites.

Otherwise the contents Browse

Although by nature screen readers read the content in a linear fashion, there are ways for users of screen readers to browse the contents otherwise.

Consider the differences between screen readers

Screen readers are remarkably similar in their features and capabilities, but there are differences between them. Keyboard shortcuts to a screen reader are rarely the same for other screen readers. The voices of different screen readers are not identical. They also have different ways to notify users about important information, such as text links which are the elements which are images, etc..

A reasonable question to ask at this stage is whether developers should care about the differences between screen readers. If the content is accessible to a brand of screen reader, will be there to other brands? Should developers customize content to reflect the different abilities and different specificities for screen readers? These questions are relevant but difficult to answer. Developers should already ensure that their content works well with several different versions of browsers on multiple platforms. It's enough work to not having to worry about different versions of different screen readers on different platforms.

The good news is that techniques that work for a screen reader almost always work for other screen readers. In some cases, a screen reader has capabilities that others do not, or handles certain types of content better than other screen readers. However, the developers almost always right when they meet accessibility standards instead of trying to adapt the content to the specific screen readers. , ce qui pourrait exclure les utilisateurs de lecteurs d'écran pour lesquels la page n'a pas été optimisée. Emphasize the differences between screen readers can lead to the undesirable situation of having pages designed just for JAWS or Window Eyes just to, which could exclude users of screen readers for whom the page n has not been optimized. It would be like optimize pages for a browser. A few years ago it was common to read in the pages marked "This page is optimized for Internet Explorer (or Netscape)." Fortunately, this practice became less frequent, and is generally frowned upon. Most Web browsers and screen readers have paid more attention to standards in recent years, so the user experience is quite consistent regardless of the technology used. No technology is identical, which can lead to intractable issues in the development but they are close enough for there to be few exceptions to the "rules" of development outlined above.

How screen readers read the content

This paragraph shows how the screen readers read and pronounce the content. It is not an exhaustive list but it will help developers understand better the functioning of screen readers. Most developers will not need more information than given in this document but those interested should either buy full versions of different screen readers, or download trial versions.

• Screen readers stop to points, semicolons, commas with, the question marks and two points.
• Screen readers usually live stop at the end of paragraphs.
• Screen readers try to pronounce acronyms and words without apparent meaning if they have enough vowels / consonants to be pronounceable, otherwise they spell out the letters. For example, NASA is an acronym pronounced as a word, while the NSF acronym is pronounced letter by letter as "NSF", the acronym URL is pronounced "earl", even though most people pronounce the letter rather letter "URL", the acronym SQL is pronounced "sequel" by screen readers, although some people pronounce it that way, screen readers pronounced letter by letter "SQL".
• Users of screen readers can stop them when they do not understand a word and can make him tell, they can even read the words letter by letter by the screen reader. When reading words letter by letter, JAWS distinguishes between uppercase and lowercase letters, focusing on capitalization.
• Screen readers read the letters when they are typed on the keyboard (they say "star" or "asterisk" to the letters typed in the password fields).
• Screen readers announce the title of the web page (tag <title> in the tag <head> ).
• Screen readers will read the alt text of images, if the alt text is present in the code. JAWS pronounces the word "graphic" before the contents of the alt text. If the image is a link, JAWS pronounces the phrase "graphic link" before the contents of the alt text.
• Screen readers ignore images without the attribute alt in the code and say nothing or else the image file name based on the preferences settings in the screen reader.
• If the image without attribute alt is a link, screen readers will read usually live link destination (the contents of the attribute href in HTML).
• s'arrête, aidant ainsi les utilisateurs à faire la distinction entre le lien Web et le texte qui suit. In early versions of JAWS, it did not stop after reading a link but its version 6, JAWS stops, helping users to distinguish between the Web and text link below. When an image and text are included in the same link, JAWS does not stop in between.
• Screen readers read the alt text of the hotspots in an image map, but not necessarily in order of appearance in the visual page. In terms of validity of the HTML, the hotspots (tags <area> ) need not follow immediately the image in the HTML (tag <img> ), but developers should not be separated in fact in the code. If the image and the spots are separated in the code, JAWS will read the alt text of the hotspots in order not corresponding to the visual display in the document.
• Screen readers can read the paragraph headings. JAWS, for example, says "as a level" before reading the contents of the tag <h1> corresponding paragraph under Level 1.
• Screen readers announce the number of links in a page when the browser has finished loading it.
• JAWS says "link on the same page" when the link destination is in the same page as the link itself.
• Screen readers inform the user of the number of rows and columns in a table when the table navigation mode is activated by the user.
• Users can navigate in all directions from cell to cell (when the table navigation mode is enabled). If the table is coded correctly, the screen reader will read the title of the column and / or line belongs to the cell when the user enters the cell.
• Screen readers inform users when they access a form. Users can activate the navigation form.
• Recent versions of screen readers can automatically detect language changes (and then change the language of the voice synthesis) when a page or a word in a page is marked in a different language. For example, if a sentence in Spanish appears in an English page, the screen reader can pronounce it in Spanish if the sentence was marked as follows: < span lang="es">Viva la patria</span >.
• Most screen readers pronounce words correctly in almost all cases, but sometimes they misinterpret the difference between homographs (words that are spelled the same but have different meanings and / or different pronunciations) . » ou « red » en fonction du contexte : « I must read the newspaper » par rapport à « I have read the newspaper « . For example (in English), read the word can be pronounced "reed" or "red" in context: "I must read the newspaper" versus "I Have read the newspaper". A phrase such as "I read the newspaper Every Day" is ambiguous to everybody and also for screen readers. This may mean that the author reads the newspaper every day, or that the author used to read the newspaper every day. » ou « red « . Depending on what the author meant, read the word in this sentence can be pronounced either "reed" or "red". » (qui signifie heureux , avec l'emphase sur la seconde syllable [ con- TENT ]) par rapport à « Skip to main content » (qui signifie l'information principale , avec l'emphase sur la première syllable [ CON -tent ]). The word happy is another example: "I feel happy" (which means happy, with the emphasis on the second syllable [con-TENT]) compared with 'Skip to main content "(which means the main information, with emphasis on the first syllable [CON-tent]).
• Screen readers read most punctuation default, such as parentheses, dashes, asterisks, etc.. but not all screen readers read the same list of default punctuation. Some do not read the asterisks default instance. Points, commas and colons are not usually read so strong but screen readers usually stop after reading. Users can set their preferences so that screen readers read every punctuation and symbols.