Sign language transmission
In a paper dedicated to the development of sign language and the deaf community in Australia, in which he also discusses the factors that might affect the future of sign languages in general, Johnston (2006: 138) distinguishes three groups of sign language users, namely, (a) deaf individuals who attain sign language outside the family (as mentioned previously, the larger number of deaf individuals who are born to hearing or deaf non-signing parents), (b) a small number of native sign language users who acquire the language in the family (possibly similar in number to that of hearing individuals acquiring the language as a mother tongue, and (c) a third group of sign language users that has been growing in number during the last decade, namely, the group of hearing learners of sign language as a second language (L2). This allows for the distinction of three types of sign language transmission (cf. Mitchell 2004: 9), namely, (a) inter-generational transmission, (b) intra-generational transmission, and (c) direct instruction. We will not delve on the latter but briefly sketch the two former types.
Inter-generational transmission. With the exception of those communities with a high incidence of deafness, this type of transmission occurs only in the rather exceptional cases of deaf children with deaf parents. Thus, for the majority of deaf children socialisation in sign language occurs outside the family, a situation that marks an important difference to that of other linguistic minorities.
Intra-generational transmission. Sociopolitical and demographic developments are affecting a tradition that can be traced back to the end of the 19th century, with the establishment of deaf schools and the gathering of larger groups of deaf individuals. For sign language transmission, educational institutions gathering larger number of deaf students have played an important role despite the circumstance that in the majority of cases they have not used or even banned the use of sign language as a medium of instruction. Indeed, Padden (1998a: 82) claims that “the school, and not the family, becomes the major socialising agent for deaf children.”
It is important to note in this context that the turn toward education of deaf students in regular schools in the second half of the 20th century (section 18.104.22.168, Plaza-Pust 2016) reduces the relevance of educational institutions for intra-generational transmission. In the deaf communities and related interest groups, this development has been observed with great concern because of the potential impact it has on the vitality of the language. As Johnston (2006: 151) remarks, the change involves a reduction of children learning sign language and relating to the deaf community in their surrounding, so that “from the linguistic point of view, mainstreaming has also negatively affected the integrity and perhaps the longterm viability of the already numerically reduced signing community.”
In this context we may advance that there is another factor affecting the vitality of the community, apart from changes in the educational area, namely, the developments in the medical sciences and hearing aid technology (hearing aids, cochlear implants). As the practice of cochlear implantation is increasing in several countries worldwide, Johnston (2006: 161) wonders on the maintenance of the “critical mass” of sign language users that is necessary for the vitality of the language, whereby “critical mass” is understood as “the minimal viable size for a linguistic community in both numbers of users and functional range of use.” Other authors acknowledge the impact of variables affecting the size of the pop?ulation of signers, but draw attention to the symbolic value attributed to the language by its users, a development that also reflects the increase of deaf activism in the course of the last years, as is explained later in this chapter (section 22.214.171.124) (Gras 2006: 196). As for the size of the population of sign language users, we will see in the next section that it is not so easy to determine.
-  There have been at least three much cited cases of communities in which sign language wasthe common means of communication, namely, Martha’s Vineyard (USA), a Mayan village inYucatan (Mexico) and Desa Kolok in Bali (Indonesia). The use of sign language by both deaf andhearing is related to the high incidence of deafness in these communities (cf. Ann 2001: 38 f. forfurther details).