Abbreviation

Abbreviation is the family name, and the family has members worth telling apart. An acronym is built from initial letters and pronounced as a word: NASA, scuba, laser, two of which have been words for so long that nobody capitalises them any more. An initialism is built the same way but read letter by letter: HTML, PDF, BBC. A contraction keeps the first and last letters and drops the middle, which is why British style writes Dr and Mr without a full stop, while a truncation cuts the end off and keeps one: Prof., Fri., etc. The rule behind the punctuation is that the full stop stands in for the letters you removed, so it belongs where the word simply stops. Whichever convention you pick, pick one and hold it: a page that writes Dr. in one place and Dr in another is reporting nothing except that two people wrote it.

Typographically, a run of capitals is a problem. Capitals are all one height, so a string of them makes a solid dark rectangle in the middle of a line, and the line’s colour goes uneven. The traditional fix is small caps, which set the abbreviation at roughly x-height so it sits in the texture of the paragraph instead of on top of it, with a little letter spacing because capitals are drawn to be fitted loosely. Real small caps come from the font; the synthesized kind CSS falls back to are shrunken capitals with the wrong stroke weight. Everything the entry on all caps says about reading speed applies here in miniature, which is a further argument for keeping the abbreviation shorter than the sentence around it.

The markup is <abbr>, and its title attribute is where good intentions go to die. A title shows as a tooltip on hover, which means it is unreachable by keyboard, unreachable by touch, and inconsistently announced by screen readers, so an expansion that lives only there is an expansion almost nobody receives. WCAG asks, at AAA, for a mechanism to get the expanded form, and the mechanism that works for every reader is much older than the web: write the full phrase out the first time and put the short form in brackets after it, then use the short form from then on. That is why the specimen above puts the expansions on the page behind an explicit control rather than behind a hover, and why <abbr> earns its keep mostly as a styling and semantics hook rather than as an accessibility feature.

The remaining trouble is pronunciation, and it is not fully solvable. Screen readers guess whether to say a string of capitals as a word or as letters, and they guess from heuristics that differ per reader and per voice, so JPEG, “jaypeg” to you, may arrive as four letters or as noise. Full stops between the letters change the guess and are worth trying when a specific initialism reads badly, but the reliable move is to spell it out in the text once. And every abbreviation you introduce is a small tax on the reader’s cognitive load: a shortening saves the writer more than it saves anybody else, so the ones worth keeping are the ones the audience already uses.