ok.lets test.
1. just open public_html/admin/controller/pages/catalog/category.php
2. find texteditor usage and clone it.
3. change name of clone field.
you'll get something like this^
//ORIGINAL FIELD
$this->data['form']['fields']['general']['description'] = $form->getFieldHtml(
array('type' => 'texteditor',
'name' => 'category_description[' . $content_language_id . '][description]',
'value' => $this->data['category_description'][$content_language_id]['description'],
'style' => 'xl-field',
'multilingual' => true,
));
//YOUR CLONE
$this->data['form']['fields']['general']['description2'] = $form->getFieldHtml(
array('type' => 'texteditor',
'name' => 'category_description[' . $content_language_id . '][description2]',
'value' => $this->data['category_description'][$content_language_id]['description2'],
'style' => 'xl-field',
'multilingual' => true,
));
4. open any category edit page.
it works for me.