Private Use Variant Subtag

Philip Newton philip.newton at
Fri Mar 30 18:56:41 CEST 2012

On Fri, Mar 30, 2012 at 18:51, Mark Davis ☕ <mark at> wrote:
>> (1) Am I allowed to just use unregistered variant subtags in the hope
> No. What you do is use the -x-, such as in:
> en-AU-x-anything

There is also the possibility of using qaa ... qtz, which are
private-use subtags for languages, and Qaaa ... Qabx, which are
private-use subtags for scripts, and AA, QM ... QZ, XA ... XZ, ZZ,
which are private-use subtags for regions.

I must admit I'm a bit puzzled at the OP's claim that "there do not
appear to be any variant subtags set aside for private use" when
"Private Use Subtags" shows up right there in the Table of Contents of (that bit being from RFC

Philip Newton <philip.newton at>

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