Hearthsong Rhyme and Reason1980

In Earthsong, the Native Tongue trilogy's long-awaited finale, the Aliens have abandoned Earth, taking their technologies with them and plunging the planet into economic and ecological disaster. Devastated, the women decide to take their failed Láadan project back underground, desperately seeking guidance from their long-dead foremothers. The women discover an ingenious solution to the problem of human violence and seek to spread their knowledge-but has their final solution come too late?