To reverence the opening of buds?
3) Were they inclined to quiet laughter?
4) Did they use bone and ivory
Jade and silver, for ornament?
5) Had they an epic poem?
6) Did they distinguish between speech and singing?
1) Sir, their light hearts turned to stone
It is not remembered whether in gardens
Stone gardens illumined pleasant ways
2) Perhaps they gathered once to delight in blossom
But after their children were killed
There were no more buds
3) Sir, laughter is bitter to the burned mouth
4) A dream ago, perhaps. Ornament is for joy
All the bones were charred
5) It is not remembered. Remember
The ‘burned mouth’ may be a reference to the chemical sprayed over North Vietnamese crops and forests to defoliate the countryside, known as  Agent Orange . It was corrosive and resulted in skin conditions, cancers and birth defects. It badly affected the local population as well as American troops. In these circumstances laughter is silenced. 
 Levertov’s reference is in keeping with the worldwide condemnation of America for targeting civilian populations. 
 
 The use of the  plosive  ‘b’ sound in ‘bitter’ and ‘burned’ emphasises the anger of the speaker towards the horrifying image the poet has created.
What Were They Like