[4] Lehtonen's first term as a missionary in Ovamboland took place in 1954–58,[5][3] and right from the start she worked at Oshigambo, teaching in the girls' school.
After the Oshigambo High School had been founded, she taught there, and when Tirronen left for Finland in the mid-1970s, she took on the responsibilities of the principal.
In addition to working as a teacher, Lehtonen also wrote, together with Kirsti Ihamäki, a history book for Standard Three.
[4] When the South African Defence Forces established a base only one-half kilometre (0.31 mi) from the school, Lehtonen protested strongly, and the base was moved to a new location two kilometres (1.2 mi) from the school.
One explanation has it that it refers to a bird, but according to another explanation it comes from the verb nyekula "to turn suddenly, swing around, fling one's head or arm, whisk its tail",[8] because when she started walking, she would always fling her head and arm simultaneously, but only once.