1. United States Department of State: Foreign language training.
https://www.state.gov/foreign-language-training/
. Accessed 29 Jan 2020
2. European Commission: Europeans and their Languages. Report (2012).
http://ec.europa.eu/commfrontoffice/publicopinion/archives/ebs/ebs_386_en.pdf
3. DataReportal Digital 2020: Global digital overview.
https://datareportal.com/reports/digital-2020-global-digital-overview
. Accessed 17 Mar 2020
4. Statista: Digital language learning global market size by language 2025 (2019).
https://www.statista.com/statistics/948857/digital-language-learning-global-market-size-language/
5. Statista: Global language services market size 2019 (2019).
https://www.statista.com/statistics/257656/size-of-the-global-language-services-market/