[XeTeX] XeTeX/TeX Live : Setting the default language

[Philip TAYLOR (Webmaster, Ret'd)]

It is important for a book on which I am currently working
that hyphenation be according to the rules of <Br.E> and not
<Am.E>.  I have just invoked TLMGR, and cannot see where the
default language should be set.  I have the file :

	hyph-en-gb.tex

and in pre-TeX Live / XeTeX days, would simply have launched
IniTeX with an appropriate steering file, dumped the format and
used it thereafter.  But I realise now that I have no idea
how such things are intended to be done with TeX Live, XeTeX
and TeXworks.

Advice sought, please !
Philip Taylor