THERE ARE FEW things sadder than a child in flight from his own family. But Danny Lynx, the 11 -year-old narrator of Ruby Slipperjack`s novel Silent Words (Fifth House, 250 pages, $12.95 paper) has good reason to hit the road. Since his mother left home, Danny`s life has been a blend of neglect and abuse. Fearing the brutal beatings of his father, Danny runs away from home, his only hope being that somewhere he will find his mother and be happy again. Danny`s trip takes him through the bush and the Ojibway communities along the mainline of the CN in northwest Ontario. Since he has little more than the clothes on his back, Danny is fed and cared for by other Natives along the way. Slipperjack, herself an Ojibway, creates a strong portrait of a boy learning to trust and accept his heritage from the kind families and the elders who take him in for lengthy periods. But there`s a plodding quality to the descriptions of trapping, canoeing, fishing, and endless scenery. The plot loses any tension, as dramatic events - a fire, an accidental drowning, a fatal heart attack - are given no more emphasis than catching a sturgeon for supper or meeting a wolf in the forest. Though the pace suddenly picks up close to the end, the conclusion seems both contrived and hasty. Burdened with detail, Silent Words suffers from too many words and not enough stories.