Many children around the world are multilingual. Recent estimates suggest that approximately 7,000 languages are currently spoken worldwide in only 196 Countries (Simons & Fennig, 2018). This suggests that the vast majority of the world’s population is consistently exposed to two or more languages and can be considered multilingual (Baker, 2006; Jonak, 2015; Marian & Shook, 2012). Reported rates of multilingualism in places such as Europe (67%), Canada (55%), India (25%), and the United States (20%) indicate that multilingualism is both common and increasing (Luk, 2017; Office of the Registrar General & Census Commissioner, India, 2001). The current rates for the number of multilingual children are often even higher than that for adults. For example, in the U.S. 26% of 5 to 17 year children nationwide are multilingual, although rates differ by state. In the U.S. the state of California has the highest percentage of multilingual children at 43%, while only 2% of children in West Virginia are multilingual (Kids Count Data Center, 2019). An estimated 15% of children in Australia (Australian Bureau of Statistics, 2006), 18% to 25% of children in Canada (Schott et al., 2021), 29% of children in parts of Spain (Statistical Institute of Catalonia, 2007) and 90% of children in Singapore (Wu et al., 2020) grow up multilingual.   
It is much more challenging to find estimates of the number of children under age three that are multilingual. Data from Canada provides unique insight into estimates of infant and toddler multilingualism and how rates differ geographically even within the same country. Across Canada, 15.6% of children aged 0 to 4 and 20.4% of children aged 5 to 9 years of age are multilingual. Broken down by province/region, the rate of child multilingualism was highest in Northern Canada (Yukon, Northwest Territories, and Nunavut), with nearly one in three children speaking two languages at home, in most cases an Indigenous language and English. Nearly one in four children aged 0 to 4 in Toronto, Vancouver, Ottawa, and Montréal, spoke at least two languages at home. In Calgary and Edmonton, rates were one in six for children aged 0 to 4. Provinces with larger cities had higher overall rates of multilingualism (i.e., British Columbia, Alberta, Ontario, and Quebec). Across all provinces, the rate of multilingualism among 5 to 9 year olds was higher than 0 to 4 year olds, which could be due to some children acquiring a community language at school and then starting to use that language at home. This pattern has been documented in the United States for native Spanish-speaking children learning English (Hammer, Lawrence & Miccio 2008). 
Rates of multilingualism amongst children between 0 to 9 years of age across Canada
Children who are multilingual are a highly diverse group from varied family backgrounds with a wide variety of life and language experiences. In the U.S., children in a multilingual home, are likely to have parents without a high school education, are likely to be growing up under economic challenges, and are likely to be raised in specific cultural contexts that may differ from mainstream U.S. norms. (Winsler et al., 2014). In addition, it has been found that children with immigrant parents (who are likely to be multilingual) are more likely than those with parents born in the U.S. to live in two-parent families (Hernandez & Napierala, 2012); immigrant mothers are more likely to be married, less likely to be depressed, and more likely to have larger families than nonimmigrant mothers (Mistry, Biesanz, Chien, Howes, & Benner, 2008). These sociocultural factors represent a constellation of strengths and potential challenges for multilingual children growing up in the U.S.