Actually I think it's reflective of the bond and degree of attachment that the family has with the dhh child. Other hearing people aren't sure how to take DHH children and therefore will not interact with them as much as someone who has normal hearing. Families however know their children and that results in the greater oral interaction that we see in these studies.
I never felt that my own family hypernunciated with me. They just knew me. Same with all my hearing friends today. They *know* me and know exactly what I am about. But with strangers I can see the hesitation to begin with, which then dissipates when they get to know me as a person.
