This book examines the survival of the French language in an English environment. Manitoba is one of Canada's Western provinces. Its population, mainly English speaking, includes a French minority, whose roots date back to the 18th century. This book describes the variety of French now used in Manitoba, particularly its history and lexicon. This linguistic description, both synchronic (1990-1991) and diachronic (1963-1991), is based on fieldwork targeting the 'available lexicon' of young speakers (ages 10 to 12). Their vocabulary is statistically evaluated: each word is paired with its lexicometric index (frequency in a given semantic field). This lexicometric corpus includes collected words of all types: French words old and new, canadianisms and anglicisms. It represents the basic vocabulary in use in Manitoba today and demonstrates how a language innovates and defends itself lexically.