  It has long been recognized that interpretation of the ‘wild child’ literature — helpfully surveyed in Skuse 1993 — is confounded by the fortunate rarity of these ‘natural experiments,’ the generally poor reporting of them, and the other environmental factors (abuse, malnutrition, neglect, etc.) that often go along with extreme linguistic deprivation.  However, in work pioneered by Goldin Meadow and colleagues (e.g., Goldin Meadow and Mylander 1983, 1990), a new population of individuals, who are linguistically but not otherwise deprived, has begun to be studied. Deaf but otherwise normal children of hearing parents who are neither educated in sign language nor sent to special schools for the deaf do not acquire language, although they usually develop their own rudimentary signing systems, called ‘homesign,’ to use with their families. Studies of what happens to such children after they are exposed to natural languages (signed or verbal) at various ages promise to offer new insights into the critical and sensitive period hypotheses.