It takes more time and effort and delicacy to learn the silence of a people than to learn its sounds. Some people have a special gift for this. Perhaps this explains why some missionaries, notwithstanding their efforts, never come to speak properly, to communicate delicately through silences. Although they 'speak with the accent of natives' they remain forever thousands of miles away. The learning of the grammar of silence is an art much more difficult to learn than the grammar of sounds.