other values.
@item style
An optional additional style name. Usually it is empty---most XLFDs
-have two hyphens in a row at this point.
+have two hyphens in a row at this point. The style name can also
+specify a two-letter ISO-639 language name, like @samp{ja} or
+@samp{ko}; some fonts that support CJK scripts have that spelled out
+in the style name part.
@item pixels
The font height, in pixels.
@item height
@item :script
The script that the font must support (a symbol).
+@item :lang
+The language that the font should support. The value should be a
+symbol whose name is a two-letter ISO-639 language name. On X, the
+value is matched against the ``Additional Style'' field of the XLFD
+name of a font, if it is non-empty. On MS-Windows, fonts matching the
+spec are required to support codepages needed for the language.
+Currently, only a small set of CJK languages is supported with this
+property: @samp{ja}, @samp{ko}, and @samp{zh}.
+
@item :otf
@cindex OpenType font
The font must be an OpenType font that supports these OpenType
`:lang'
-VALUE must be a symbol of two-letter ISO-639 language names,
-e.g. `ja'.
+VALUE must be a symbol whose name is a two-letter ISO-639 language
+name, e.g. `ja'. The value is matched against the "Additional Style"
+field of the XLFD spec of a font, if it's non-empty, on X, and
+against the codepages supported by the font on w32.
`:otf'