So far, I haven't been able to extract the xml:lang attribute using XML::Parser. It seems to ignore attributes with the xml: prefix.
My experience doesn't match yours. I can clearly see the attribute 'xml:lang' in the list of attributes. 
use XML::Parser;
use Data::Dumper;

my $parser = XML::Parser->new(Handlers =>
  {
    Start => sub { print Dumper [ @_[1 .. $#_] ] }
  }
);
$parser->parse(\*DATA);

__DATA__
<FILE>
<FOO xml:lang="en">
<BAR/>
</FOO>
<FOO xml:lang="ru">
<BAR/>
</FOO>
</FILE>

[download]
Result: 
$VAR1 = [
          'FILE'
        ];
$VAR1 = [
          'FOO',
          'xml:lang',
          'en'
        ];
$VAR1 = [
          'BAR'
        ];
$VAR1 = [
          'FOO',
          'xml:lang',
          'ru'
        ];
$VAR1 = [
          'BAR'
        ];

[download]
Anyway: you might be interested in using a parser that can handle XPath, as it might make filtering out just the contents you want, just a little bit easier.

Although personally, I think XML::Parser is fine... :)

In reply to Re: Parsing xml:lang attribute by bart
in thread Parsing xml:lang attribute by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.