I lived in Zambia for a year around 2005, and my impression was that this 'nation-building' is one thing that Kaunda did really quite well. There is a strong sense of identity of being Zambian in parallel to the tribal identity. One way of achieving this was stationing secondary school students(almost all secondary schools are boarding schools) and young public employees (and in 70s quasi-socialist Zambia almost everyone with a job was a public employee) in regions other that their original tribal region. As a result, very many people married into different tribes, and very many people now have several tribal identites, which as a result aren't very strong.
Also they are indoctrinated that 'tribalism' is a bad thing, and they learn a lot about Bismarck in school. There is also a bantu language that isn't really associated with one of the major tribes but is a kind of lingua franca beside english in the urban centres.
Yes I believe that is the reason. Not a perfect analogy but I guess the point is that a nation can be united from what used to be a collection of fiefdoms.
I guess Italy would be a better comparison, because that didn't used to be a nation. Germany was united by culture and language for a while. (Only 1 in 40 people spoke what later became standard Italian upon unification.)
But I guess Germany is the more aspiring role model.
Also they are indoctrinated that 'tribalism' is a bad thing, and they learn a lot about Bismarck in school. There is also a bantu language that isn't really associated with one of the major tribes but is a kind of lingua franca beside english in the urban centres.