The predominance of English in many sectors, such as world trade, technology and science, has contributed to English-speaking societies being persistently monolingual, as there is no relevant need to learn a second language if all dealings can be done in their native language;[16] that is especially the case for English-speakers in the United States, particularly the Northern United States and most of the Southern United States, where everyday contact with other languages, such as Spanish and French is usually limited. The country's large area and the most populous regions' distance from large non-English-speaking areas, such as Mexico and Quebec, increase the geographic and economic barriers to foreign travel.[17] Nevertheless, the requirement for all school children to learn a foreign language in some English speaking countries and areas works against this to some extent. Although the country is economically interdependent with trade partners such as China, American corporations and heavily-Americanized subsidiaries of foreign corporations both mediate and control most citizens' contact with most other nations' products.