Do children learn language from rich (enough) input or do they invent it more or less on their own, driven by some innate program? That is a question that has kept great scientists busy, particularly Noam Chomsky.
And so with modern gesture research (post Chomsky) and modern sign language research (post Stokoe/Tervoort) the question became important which role gesture and emerging sign language skills plays in the development of language and cognition in hearing children and deaf children, see the work of Susan Goldin-Meadow and co-workers in particular.
A famous case is the discussion surrounding the documented invention of Nicaraguan Sign Language by successive generations of deaf children (by Judy Kegl and others).
But it appears that not only children can create language. A local newspaper here reported that the oldest man in the Netherlands (age 106) lost hearing and speech and invented a ‘sign language’ with his daughter in law to communicate.
Adrianus van der Vaart and daughter-in-law Corry created a sign language (source: AD)
Did ‘Opa Arie’ take a dip in the fountain of youth?
Is there no such thing as a critical age of acquiring/inventing a language?
Or did the newspaper exaggerate?
Given the nature of newspapers it is likely that the AD exaggerates. Besides, any sort of gesture system is quickly called a ‘sign language’ in the Netherlands, and little distinction is made by the general public between ‘genuine Sign Language of the Netherlands (NGT)’ and other ‘gebarentaal’.
Further research is needed urgently however, before it is too late. The potential ‘Wilnis Sign Language’ (Wilnis is an isolated village in the Netherlands with a remarkable population of elderly people with bad hearing) should be documented by the likes of Judy Kegl? Can anybody send in a linguist?