But it seems to me that much of the interesting data is mine. As I grew, my language development not only contrasted with Fern’s but also introduced a perfectly predictable x-factor that undermined all such comparisons. Ever since Day and Davis published their findings in the 1930s, there’s been a perception that twinness affects language acquisition. New and better studies took place in the 1970s, but I’m not sure our parents were looking in their direction yet. Nor would such studies have been completely relevant to a situation such as ours, where the twins had such disparate potentials.
