Daud Hassan Ali, 64, and Rehana Ahmed, 33, both from Birmingham, were killed alongside two Kenyan teachers in the town of Belet Weyne.
They are believed to have been killed in a raid by an Islamist Al-Shabab militia.
Mr Ali was born in Belet Weyne, but moved to England in 1967 and trained as a teacher. He taught at Sefton Park Boys' Secondary School in Liverpool and Thatto Heath Primary in St Helens, before working as an educational psychologist for Birmingham city council.
He took early retirement in 2004 to set up the 170-student school in Somalia, and was joined by Ms Ahmed, the daughter of a friend, who had taught at Bournville College in Birmingham.
Mr Ali had hoped to give children in his war-torn birthplace a better future by providing them with a liberal education in English, which followed the national curriculum in England.
But his wife, Margaret Ali, told The TES that some viewed him with suspicion because he was a Christian. "They called him a rude name that means infidel," she said. "I think the militia got in the town. They were all pumped up with adrenaline, so they decided to 'see to that infidel'."
But she said nobody at the school had tried to convert anyone to Christianity. "There were no Bibles in the school library, and no Christian literature," she said.
"And the history syllabus that Rehana wrote was very much from a Muslim perspective."
Just last month, Mrs Ali had warned on the project's website of the dangers, saying raids by Islamist militias had delayed the opening of new school buildings.
A former colleague in Bournville College's language and cultural studies department said Rehana's lively personality and sensitivity to people's needs had helped many of her students achieve in life.
Sean Gardner, the college's programme manager, said: "Her work in Somalia was one of the happiest times in her life, which is exactly like the Rehana we remember."