private function getPluralForms()
    {
        // lets assume message number 0 is header
        // this is true, right?

        // cache header field for plural forms
        if (is_null($this->pluralequation)) {
            if (isset($this->cache_translations[''])) {
                $header = $this->cache_translations[''];
            } else {
                $header = '';
            }
            $expr = $this->extractPluralsForms($header);
            $this->pluralequation = $this->sanitizePluralExpression($expr);
            $this->pluralcount = $this->extractPluralCount($expr);
        }

        return $this->pluralequation;
    }