IN RECENT years, a married couple in the United States developed a pidgin-like patois (for their own use) out of three languages that one or the other knew well but both did not share. The following account, while telling something of their story, looks at how such a private ‘language’ can impact negatively on second-language acquisition. The study seeks also to gauge the effect of this personal ‘pidgin’ on Pierre, a native speaker of Wolof, and on his acquisition of English, a language he needs to know. In one sense their private language is a success, but in another it is a problem, because Pierre needs to become fluent in the language of his new home. He and Mary have created a language style that suits their daily needs, but their very success and originality may be preventing Pierre from moving on into conventional English.