Yes, Ingrid Jonker did use the language in her poem effectively to create a sense of a particular time and place in "The child is not dead". The event that shes specifically refering to is when a child was shot dead by soldiers in Nyanga. For example, she says in her poem, "The child is not dead not at Langa nor at Nyanga not at Orlando nor at Sharpeville nor at the police station at Philippi where he lies with a bullet through his brain". In this phrase from the poem she's directly referring to the events at multiple places where significant events have happened. Such as referring to Sharpeville Massacre and the later events at Langa and Nyanga where the child was shot in the head. She also says in her poem, "The child is the dark shadow of the soldiers on guard with rifles Saracens and batons the child is present at all assemblies and law-givings". This phrase in the poem demonstrates the kind of time it was in Africa as she also later says, "this child who just wanted to play in the sun at Nyanga is everywhere". It talks about a time when children were not able to be children because of the pressing of apartheid. By giving these specific examples and phrases Ingrid Jonker did use language effectively to create a sense of a particular time and place.
Hope this helps!