Despite the gradual global fall in the reliance on language and colonial ties, migration within the South still relies primarily on physical proximity. It is a fact that South-South migration stocks between neighbouring countries are more prevalent than between South and North. Forty-five out of 63 developing countries (71%) whose emigrants have as their first destination another developing country share a border with that country. Mexico is the only developing country (out of 78) sharing a border with the first country of destination of its emigrants, namely the United States, when that country is developed. Even though transport costs are falling worldwide, a solid land border affords easier travel and lower opportunity costs.
In addition, the formalities for entering a country are easier to circumvent or simply ignore in many countries of the South than in the North; what is regulatory and legal in the South is not necessarily reflected in reality. Governments are overburdened with other priorities, which means that, with a limited administrative capacity, immigration controls are often overlooked. In cases where that issue is indeed dealt with, it is usually and increasingly done under the pretext of national security concerns. This has direct implications for integration. As a large amount of labour movements in the South can be attributed to short-term movements to areas where borders are often left unmonitored, the migratory system in this sense is smooth and seamless - and pro-cyclical with the demand for labour.
The neighbourhood effect means it is easier not only to emigrate but also to integrate into another country. 13 In fact, cultural and linguistic ties play a primary role, particularly for lower-skilled (and temporary) immigrants. Bengali speakers from Bangladesh favour neighbourhoods in Delhi where they can find people speaking their language. Similarly, the Ewe from Togo seek work in the eastern regions of Ghana, where Ewe is the primary language, a factor that facilitates their seasonal migration for work in the cocoa plantations. Some languages have even evolved as primary migratory route languages, joining people with similar customs across large spaces. Such is the case with the Hausa language and the Islamic faith, facilitating trade relations in West Africa for centuries. These ties go beyond language: religion, food, working habits and family customs all help in forming immigration routes (Amor et al., 2010).
These examples demonstrate that it is not necessarily the ability to speak the country's national language that facilitates migration and integration. Bengali is a recognised official language in parts of India, but not in Delhi. In Ghana the national language is English while in Togo it is French. Hausa is a recognised national language in only two countries (Niger and Nigeria) despite its wide use across West Africa, and even beyond. International borders split groups with similar languages and cultures, and the migratory links that continue to bind them after decades, sometimes centuries, are international in nature.