I believe that Owen voice is one distressed over the war and what it brought to the soldiers. Owen uses imagery to describe the exhaustion by telling the reader that they were limping and dragging their feet. He saw and smelt the clouds of gas, he saw the effects of the gas from hearing a seemingly sick man yelling, coughing and choking on blood.
He uses simile by comparing the soldiers to old beggars and comparing the coughing soldiers to sick, old people. The author uses a metaphor by stating the soldiers marched asleep to tell the reader that they were marching while tired and exhausted and not that they were literally asleep. He also uses metaphor to describe that they were exhausted and that their exhaustion is affecting their ability
He uses simile by comparing the soldiers to old beggars and comparing the coughing soldiers to sick, old people. The author uses a metaphor by stating the soldiers marched asleep to tell the reader that they were marching while tired and exhausted and not that they were literally asleep. He also uses metaphor to describe that they were exhausted and that their exhaustion is affecting their ability