Originally published in 2018.

An Apple iOS beta appeared in mid-2017 with a typographic change that would modify a common, long-running convention of typing two hyphens, like –, and having autocorrection turn that into — an “em dash” or “long dash.” From reports and testing, it looked like – would change to –, or an “en dash.”

You may never have heard of an en dash if you’re not a print or Web designer or otherwise interested in the intricacies of formatting things. It looked like Apple was going to require typing --, a convention that also appears in TeX, a mathematical formatting language developed by Donald Knuth, to get an em dash.

I remembered to check back on this just today, and Apple fortunately didn’t pursue that course. Instead, it uses contextual clues, based on how em dashes and en dashes are typically used, which I’ll describe below.