The lang attribute specifies the primary language used in contents and attributes containing text content of particular elements.
There is also an xml:lang attribute (with namespace). If both of them are defined, the one with namespace is used and the one without is ignored.
In SVG 1.1 there was a lang attribute defined with a different meaning and only applying to <glyph> elements. That attribute specified a list of BCP 47 language tags. The glyph was meant to be used if the xml:lang attribute exactly matched one of the languages given in the value of this parameter, or if the xml:lang attribute exactly equaled a prefix of one of the languages given in the value of this parameter such that the first tag character following the prefix was "-".
This value specifies the language used for the element as a valid BCP 47 language tag.
The most common syntax is a value formed by a lowercase two-character part for the language and an uppercase two-character part for the region or country, separated by a minus sign, e.g., en-US for US English or de-AT for Austrian German.
