From history, Akirinyaga are more Gikuyu than the rest. What those foolish elders would have done is to seek to have Akirinyaga recognised as AGikuyu with the rest having to seek their identities. Needless to say, this one is a non-issue and dead on arrival.

I agree on Kiambu people being from Murang'a but Nyandarwa seems to be a mix

For Kirinyaga people, why do they speak differently from Nyerians if they emanate from them? I tend to believe @Njung'e that Kyuks originated from that side due to some words which still exist among Akirinyaga but rarely used by the rest of Kyuks like naii(evil), njara, abai

You mean Kiembu?

There is nothing like Kirinyaga tribe. They are just Agikuyu with Akamba accent. The vocabulary is the same but pronunciation is different. Even Embu's should be classified as Agikuyu.

From the language, i think the akirinyaga are product of intermarriage between gaki and aembu/ameru - these three peoples all lived along the edge of mt kenya and used to interact even before mzungu arrived to spoil the scene. methinks if mzungu hadnt come most of the gikuyu peoples would have by now disintegrated into several sub-tribes.