What did the narrator say about her second year at Radcliffe? Why did she consider the second year in the college as the happiest year of hers?

Helen Keller wrote her autobiography, The Story of My Life, as a first person narrative.  She described her second year at Radcliffe College as "the happiest."  This was because Helen enjoyed her classes very much in her second year at the college.  She studied "subjects that especially interest[ed]" her, such as Shakespeare and Elizabethan Literature, as well as philosophy and economics.  Helen also took other classes that year, such as those in history, Latin comedy, and English composition.  

Professor Kittredge, who was Helen's Shakespeare professor, was a man who she considered to be a "great scholar."  She loved how he presented Shakespeare's writings.  Studying the subject of philosophy gave Helen a "sympathy of comprehension into the traditions of remote ages and other modes of thought."  

Helen was a person who loved learning.  As a child, she spent many years in a sort of educational darkness.  She could not effectively communicate anything beyond basic wants and needs.  She could not read or write.  When her teacher, Annie Sullivan, arrived in her life, Helen entered a new world.  This was when she truly began to value learning.  Helen became a lifelong learner.  She valued education and worked hard in school.  It is no surprise that Helen loved learning at Radcliffe, despite challenges and difficulties.  Helen especially loved studying her favorite subjects, such as literature and philosophy.