30578 Hai Phong Sign Language 1000-9999 "Since there has never been a census of deaf people in Viet Nam, the real number of signers is unknown. However, some estimate of the number of signers can be made.... Using United Nations estimates of 1 person out of every 1,000 person born profoundly deaf or becoming profoundly deaf at an early age, there would be an estimate of 1,837 deaf people living in the area where HPSL is used. The estimated number of users of HPSL is up to 1,800 users." Hai Phong Sign Language On ~1800 1000-9999