The English term "chair" matches the Yoruba term "àga"

Missionaries and the Written Language
The language was standardized in the 19th century. It was adopted by all the dialects to create some uniformity in Yoruba in spite of the differences. The 19th century was another effort to standardize the language. Initial efforts were first made in the 17th century by English missionaries and priests. They developed a written language using the Ajami script. Vocabulary lists and grammar were developed and this helped later when Bishop Samuel Crowther used the Latin alphabet to translate a Yoruba-language Bible.
Famous Authors
Yoruba’s most famous author, D.O. Fagunwa, wrote and published Obgoju Ode Ninu Igbo Irunmole which is the first full novel in this language. Other authors include Amos Tutuola. His books have been translated many times. Early themes in literature include the Yoruba people’s history and oral traditions.
Standard Debate
There is some disagreement about what standard Yoruba is. Most people consider it to be based on Crowther’s work It’s also the standard language taught in schools and to language learners.