When you think about it, both English and Kiswahili are foreign but English gives Kenyans a greater edge. Swapping national language changes nothing. There is someone under the illusion that it is Kiswahili that killed tribalism in Tanzania. I don't think so
Tzians had a non-tribal first president whereas we had a class A tribalist of the highest order who had Kikuyus swearing blood oaths about the House of Mumbi and all manner of unbelievable stuff. He messed the tribal relations with all sorts of policy decisions, not least of which was land: that's what it comes down to, re the differences btw us and Tz. Even the first E.A.C really broke up because of the same greed in Nairobi that denied us true nationalism within our own borders. A true Pan-Africanist and a Total tribalist just arent gonna leave a similar legacy where the unity of the people is concerned.
Anyway, if language has a role, it's that Tzians killed their ethnic languages, not magic Swahili.
But Swahili is a Bantu language, not foreign. Arabic loanwords, that's what its got, but it's Bantu, through n through. Does that mean we should kill English? That's insanity. No one will agree to that. Besides, Swahili is already our national language. We have two official languages. Whoever put that there amepitwa na wakati. We should be improving the way English is taught outside Nairobi, not following Tz.