Preliminaries

Methodology of data presentation and analysis

A qualified Deaf BSL tutor taught Christopher a conventional (Signature Level 1) BSL class once a month for a year, concentrating on the core grammatical properties of the language. Over twelve months, there were accordingly twelve hours of formal teaching, which was supplemented by conversation with a native (Deaf) signer, who went over the same material in a less formal context between classes.

The total amount of BSL contact (formal teaching and informal interaction) was therefore about twenty-four hours. Although the curriculum was divided into formal lessons and informal discussions, the teaching was sufficiently flexible for both types of session to contain both types of material. By way of comparison, this is more than twice as much as Christopher's exposure to each of Berber and Epun, the other (spoken) languages we had taught him previously (see Smith et al., 1993; Smith & Tsimpli, 1995). In teaching Christopher these new languages we had left him with tape-recorded and written versions of the material he had been exposed to, and homework exercises to complete and post back to us. There were no further texts or documentation in these languages. In teaching him BSL we could not leave him any written material, but we did provide him with a BSL dictionary and some video material. He used these sporadically, but he never mastered the transcription used in the dictionary, and soon broke the video machine. In fact his use of any of the material for spoken or signed languages appears to have been minimal. It is important to emphasise the difference between BSL on the one hand and Berber and Epun on the other. If his excellent memory is devoted largely to the written form of language, we would expect him to have greater difficulty learning BSL than languages with a written mode.