If Apple does it correctly, 1.0 means that there will be no backward incompatibilities until a hypothetical version 2.0.

As a user of a not yet 1.0 language (Elixir, though it has reached release candidate status), backward incompatibilities can be a pain to deal with. The reason: third-party libraries that may or may not be updated, more or less quickly.

And yet it's absolutely necessary to get things right while you design the language, because every single mistake will be carried forward practically forever: see Python 3 as to why it's really hard to fix a language...

> Typically, when people say that a language "reached 1.0", they mean the very end of that process.

That's wrong for practically all cases I know of (Java, C#, Python, Perl).

Ah. Well, other languages also get new features, improved performance, and refined syntax after 1.0. Are you objecting to the implication that the pace of development here will be more rapid, or an assumption that they plan on making backwards-incompatible changes?

I wasn't aware that hitting 1.0 means all development ceases.

Only when languages die.