Answer:
He had to learn the language in order to do missionary work and translate the Bible. Moffat was the first person to translate the Bible into the Setswana language.
Step-by-step explanation:
Setswana language is the Bantu language spoken by Tswana people in Southern Africa. Methodist missionary Robert Moffat moved amongst them and learned their language to convey the faith and words of God. He was the first translator of the Bible into the Setswana language, which is his most important work and the main benefit of his knowledge of the language.
His additional work included the opening of the mission station, church, and Christian church. He has translated other sacred texts into Setswana, brought a printing press and printed them in this language, translated books other than the Bible, and wrote down the rules of Setswana. His work was the first major work published on this language. His son Robert has also published work on this language.