Among the manuscripts in Charles R. Boxer's collection, known as the Boxer Codex, there is an anonymous report from 1590 that described their method of writing, which is still used today by the tribes of Mindoro and Palawan to write their own script:
Sa koleksyon ni Charles R. Boxer, na kilala sa pangalang Boxer Codex, may isang lumang sulat-kamay na ulat mula sa taong 1590. Ipinaliwanag ng di-ipinakilalang manunulat ang sinaunang pamamaraan ng pagsulat, na ginagawa pa rin ng mga tribo sa Mindoro at Palawan hanggang ngayon: