Language is very powerful that it can easily indicate where a pearson person comes from. Immediately a man speaks a particular language, the closets person will quickly identify his root. This is the case of the Yorubas in Nigeria and their brothers in Benin Republic.
How Did this Happen
Apart from the slave trade that moved most Africans to other parts of the world, the 1884/1885 Berlin West African Conference was a major instrument for dividing brothers into different countries.
According to Wikipedia, Ketu is a historical region in what is now the Republic of Benin, in the area of the town of Kétou (Ketu). It is one of the oldest capitals of the Yoruba-speaking people, tracing its establishment to a settlement founded by a descendant of Oduduwa, also known as Odudua, Oòdua and Eleduwa. The regents of the town were traditionally styled "Alaketu", and are related directly to Ile-ife in present-day Nigeria. Source
Ewe traditions refer to Ketu as Amedzofe ("origin of humanity") or Mawufe ("home of the Supreme Being"). It is believed that the inhabitants (or at least some) of Ketu originally belonged to the Oyo people of Nigeria and were pressed westward by a series of wars between the 12th and the 15th centuries. In Ketu, the ancestors of the Gbe speaking peoples (Ewe, Fon, Aja etc.) separated themselves from other refugees and began to establish their own identity, but were pressed even further westward by the Yoruba during the 14th and 15th centuries. Source
Without questioning and understanding the language patterns of the people, some Yoruba people were kept in Nigeria, while others were kept in Benin Republic through the help of the Berlin West African Conference of 1884/85.
A Kingdom Divided into Nigeria and Benin Republic
The Punch newspaper interview with Oba Abdul-Wahab Adio Ogunjin.
Ologunba of Ogunba town in Benin Republic, Oba Abdul-Wahab Adio Ogunjin, is a Yoruba Oba whose domain falls within Nigeria and neighbouring Benin Republic. Ogunjin, who was recently in Ile-Ife, Osun State for Olojo Festival, speaks to BOLA BAMIGBOLA about the challenges confronting Yoruba people in Benin Republic, the need to preserve Yoruba culture and tradition, among other issues.Source
According to him, one half of his kingdom is in Nigeria while the other is in Benin Republic. I am the Secretary-General of Federation of Yoruba Obas in Benin Republic. Since the reign of the late Ooni of Ife, Oba Okunade Sijuade, we have been coming here to celebrate this festival. The reason for coming to Ile-Ife is to maintain a very good relationship with our source; to ensure there is a good relationship between traditional rulers in Yorubaland and those of us in the Diaspora. This will enable us to organize some of the festivals that we have in Yorubaland in Benin Republic.Source
Is Irredentism the way Forward
The idea of irredentism is craved when there is high level of oppression from the host nation. Irredentism might not be the solution of the Yorubas in Benin Republic, what they need to do is to constantly maintain their cultural heritage, which has been preserved for centuries.