In multilingual societies, often language use varies by domain. For example, one language (in Africa often a European one) is used for formal situations (like governmental exchanges) and another used for familiar ones. But this language use can be varied to give messages of power on one side, or solidarity on the other (among other things).
Take, for example, the following exchange in Nigeria using English (formal, official) and Igbo (local, ethnic identity):
Traffic Officer: I would like to see your vehicle registration, your driving license and your insurance papers, please.
Motorist: I'm sorry. I don't have them here. They're at home.
Traffic officer: In that case you will park the car here and go and get them.
(At this point the motorist hears another officer address the traffic officer in Igbo)
Motorist: Enyi, biakam kowalu gi. Kedu ka isi emezi etua? (Friend, come let me explain to you. Why are you acting like that?)
Traffic officer: I have told you what to do. This is not a matter for speaking Igbo.
(From Nwoye, Onuigbo G. 1992: 374. Linguistic politeness and socio-cultural variations of the notion of face. Journal of Pragmatics, Vol 18(4), Oct 1992, 309-328.)
In this example, the motorist is trying to appeal to the solidarity of the traffic officer in a shared ethnic identity. However, the officer rejects this appeal and keeps speaking the language of power.
This type of language use can speak to one reason for Bible translation -- that of identity. When the Bible is in a second language (especially a dominant, language of "power") God can seem distant. With Bible translation, people can see that God is one of them, that he speaks their language.