<unk>  refers to deafness that occurs before learning speech or language. Speech and language typically begin to develop very early with infants saying their first words by age one. Therefore,<unk>  is considered to occur before the age of one, where a baby is either born deaf (known as congenital deafness) or loses hearing before the age of one. This hearing loss may occur for a variety of reasons and impacts cognitive, social, and language development.
Prelingual deafness
Cortical deafness
Sensorineural hearing loss
Hypoglossia
Nonsyndromic deafness
Conductive hearing loss
Maxillary hypoplasia
Spatial hearing loss