$fields = array(
'author' => '<p class="comment-form-author">' . '<label for="author">' . __( 'Name' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
'<input id="author" name="author" type="text" value="' . esc_attr( $commenter['comment_author'] ) . '" size="30"' . $aria_req . ' /></p>',
'email' => '<p class="comment-form-email"><label for="email">' . __( 'Email' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
'<input id="email" name="email" type="text" value="' . esc_attr( $commenter['comment_author_email'] ) . '" size="30"' . $aria_req . ' /></p>',
'url' => '<p class="comment-form-url"><label for="url">' . __( 'Website' ) . '</label>' .
'<input id="url" name="url" type="text" value="' . esc_attr( $commenter['comment_author_url'] ) . '" size="30" /></p>',
'categoria' => '<p class="comment-form-categoria"><label for="categoria">' . __( 'categoria' ) . '</label>' .
'<input id="categoria" name="categoria" type="text" value="' . esc_attr( $commenter['comment_author_categoria'] ) . '" size="30" /></p>'
);
$commenter = wp_get_current_commenter();
$req = get_option( 'require_name_email' );
$aria_req = ( $req ? " aria-required='true'" : '' );
$fields = array(
'author' => '<p class="comment-form-author">' . '<label for="author">' . __( 'Name' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
'<input id="author" name="author" type="text" value="' . esc_attr( $commenter['comment_author'] ) . '" size="30"' . $aria_req . ' /></p>',
'email' => '<p class="comment-form-email"><label for="email">' . __( 'Email' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
'<input id="email" name="email" type="text" value="' . esc_attr( $commenter['comment_author_email'] ) . '" size="30"' . $aria_req . ' /></p>',
'url' => '<p class="comment-form-url"><label for="url">' . __( 'Website' ) . '</label>' .
'<input id="url" name="url" type="text" value="' . esc_attr( $commenter['comment_author_url'] ) . '" size="30" /></p>',
'categoria' => '<p class="comment-form-categoria"><label for="categoria">' . __( 'categoria' ) . '</label>' .
'<input id="categoria" name="categoria" type="text" value="' . esc_attr( $commenter['comment_author_categoria'] ) . '" size="30" /></p>'
);
$comments_args = array(
'fields' => $fields,
'title_reply'=>'Titulo respuesta',
'label_submit' => 'Eviar'
);
comment_form($comments_args);