it leaves out any character with accents, etc.

A quick look at the module's source reveals that there is a line (TokeParserTokenizer.pm:61)

    #Remove HTML directives
    $text =~ s/\Q&\E.*?\Q;\E/ /g;
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which replaces any HTML character entity references like ä with a space (the extra quoting of '&' and ';' in that regex is superfluous, btw, but that's another issue).  I.e., it would turn content like "äbçdèfoo" into " b d foo".

You could try commenting out that line.  Or maybe replace it with

    decode_entities($text);
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and add use HTML::Entities; near the top of that package.  That should turn the above content string into "äbçdèfoo".