In 2001, females made up 51.2% of the amalgamated Ottawa population, while the median age of the population was 36.7 years of age. Youths under 15 years of age comprised 18.9% of the total population, while those of retirement age (65 years and older) comprised 11.4%.
Bilingualism in Ottawa became official policy in 2002, making all municipal services available in both of Canada's official languages (Canadian English and Canadian French). Nearly 300,000 people, or 37% of Ottawa's population, can speak both languages, As such it is the largest city in Canada with both English and French as co-official languages. Those who identify their mother tongue as English constitute 62.4 percent, while those with French as their mother tongue make up 14.2 percent of the population. In terms of respondents' knowledge of one or both official languages, 59.9 percent and 1.5 percent of the population have knowledge of English only and French only, respectively; while 37.2 percent have knowledge of both official languages. An additional 20.4 percent list languages other than English and French as their mother tongue. These include Arabic (3.2%), Chinese (3.0%), Spanish (1.2%), Italian (1.1%), and many others.
The Algonquian languages have been spoken for centuries by the Indigenous peoples and subsequently by the French coureurs des bois and voyageurs of the Ottawa valley during the 1600s and 1700s. Starting in the mid-1800s, Irish settlers of the Ottawa valley develop a distinct dialect referred to as "Ottawa Valley Twang". Traces of "Valley Twang" although rare, can still be heard in the valley's more isolated areas.
Ethnicities, visible minorities and Aboriginals
^ abIn early 2001, the Province of Ontario dissolved the former City of Ottawa by amalgamating it with eleven other municipalities to form a new City of Ottawa. The 1996 adjusted population of the amalgamated city published in the 2001 census was 721,136, while the population of the dissolved former City of Ottawa in 2001 was 337,031.
^"Table 6: Population by census subdivisions, 1871–1951". Ninth Census of Canada, 1951. Volume I: Population, General Charactertics. Ottawa: Dominion Bureau of Statistics. 1953. pp. 6–39.|accessdate= requires |url= (help)
^"Table 6: Population by census subdivisions, 1901–1961". 1961 Census of Canada. Series 1.1: Historical, 1901–1961. Volume I: Population. Ottawa: Dominion Bureau of Statistics. 1963. pp. 6–41.|accessdate= requires |url= (help)
^"Table 2: Population of Census Subdivisions, 1921–1971". 1971 Census of Canada. Census Subdivisions (Historical). Volume I: Population, Geographic Distributions. Ottawa: Statistics Canada. 1972. pp. 2–70.|accessdate= requires |url= (help)
^"Table 3: Population for census divisions and subdivisions, 1971 and 1976". 1976 Census of Canada. Census Divisions and Subdivisions, Ontario. Volume I: Population. Ottawa: Statistics Canada. 1977.|accessdate= requires |url= (help)
^"Table 4: Population and Total Occupied Dwellings, for Census Divisions and Subdivisions, 1976 and 1981". 1981 Census of Canada. Provincial series, Ontario. Volume II: Population, Geographic distributions. Ottawa: Statistics Canada. 1982.|accessdate= requires |url= (help)