What is the difference between a metaphor and an idiom?

Read the excerpt from the poem "growing up italian" by maria mazziotti gillan and answer the question that follows. when i was a little girl, i thought everyone was italian, and that was good. we visted our aunts and uncles, and they visted us. the italian language smooth and sweet in my mouth. in kindergarten, english words fell on me, thick and sharp as hail. i grew silent, the italian word balanced on the edge of my tongue and the english word, lost during the first moment of every question. source: gillan, maria mazziotti. "growing up italian." poetrymagazine.com. poetry magazine, n.d. web. 30 mar. 2011. what is the tone of this poem? what does the tone reveal about the speaker of the poem and the conflict she faces? based on this excerpt, what can you predict about the theme of the poem?