■ I have often thought it would be a blessing if each human being were stricken blind and deaf for a few days at some time during his early adult life. Darkness would make him more appreciative of sight; silence would teach him the joys of sound. (Helen Keller)
human being で一組です。human と同じで「人間」。 strickenは「打つ」のstrikeの過去分詞ですが、受身・形容詞的に「(病気・苦痛などに)襲われる」という使い方をします。
deaf は「耳の聞こえない」。 appreciative は appreciate の形容詞。appreciate は「よさがわかる・感謝する」。 joy は不可算名詞で「喜び」ですが、可算名詞になると「喜び(のもと)」という意味になります。 ヘレン・ケラー(1880-1968)は三重苦を背負ったアメリカの著述家です。
■ Character cannot be developed in ease and quiet. Only through experience of trial and suffering can the soul be strengthened, vision cleared, ambition inspired, and success achieved. (Helen Keller)