a11y = Accessibility
TL;DR: a11y is shorthand for accessibility. Those middle characters are the number one, not lower-case Ls. Say it as A-one-one-Y or A-eleven-Y.
The a11y you may see on Twitter was not invented just to help such a long word fit into a tweet. It, and others, have been around for a long time now.
It is just one variation of a numeronym, a word that can be partially represented by numbers. And while Doctor Who’s robot dog qualifies, as well as the Usenet stain of l33t-speak, in this case we are using the version where letters are replaced.
The word accessibility is thirteen letters long, but when you keep just the a and y, you will have cut eleven (11) letters. That number now goes in the middle and you have a11y.
Some Other Examples
If you work on the web and ever touch anything that crosses borders or languages, then you may recognize these two:
These are common in the translation industry and speak to some specific concepts as a result, so you can read up a bit on their history (which predate the web).
It is not uncommon for people to mistake a11y for the word “ally.” This can happen when typed or spoken. Just like those new to l10n might spell it “lion.”
You can help mitigate this by using a typeface where the number 1 looks different from a lower-case l. Even better, use a typeface where 1 is more than just a vertical line (since “a-pipe-pipe-y” can be just as confusing).
Spell Checkers and Auto-Correct
If you work in this space at all, whether by writing about it, looking for vendors, or being forced to acknowledge it as part of your job, consider adding a11y to your personal or shared dictionary.
While most of us who use it regularly will know what you mean when we see “ally,” we will all be better able to search (and discover it) if you can prevent your tech from making decisions for you.
For years I have worked a slide about a11y into nearly every one of my accessibility talks. If you speak about accessibility, you may want to do the same. Do not assume everyone in the room knows it just because they have chosen to be in that room (especially if they did not choose to be there).
On the Twitters you can see lots of activity if you follow the #a11y hashtag. Other platforms that support tagging typically have a sub-set of users who put the numeronym to use.
Within the industry you may also find folks who pronounce it “ally” and “alley” and who may use those pronunciations in puns for company, product, service, or group names.
I posted a tweet earlier today that you can share to your followers or whomever. I think it is succinct and clear, but I think I am awesome too and that has not borne itself out just yet.
I made a follow-up pun too.
Perhaps if you are really excited about accessibility you can help me lobby for people to adopt a!!y.