Hi Ale,
To get the values in an array, you have to use rwmb_meta
or rwmb_get_value
. Then parse the field options to output the labels:
$field_id = 'mb_languages';
$field = rwmb_get_field_settings( $field_id );
$options = $field['options'];
$values = rwmb_meta( $field_id );
foreach ( $values as $value ) {
echo $options[$value]; // Label
}