Final answer:
Italian sonnets consist of an octave with the rhyme scheme abbaabba and a sestet with variable rhyme schemes, while English sonnets have three quatrains and a rhyming couplet with the rhyme scheme ababcdcdefefgg, and both feature a volta which signifies a thematic shift within the poem.
Step-by-step explanation:
An Italian sonnet, or Petrarchan sonnet, is characterized by its 14-line structure in iambic pentameter, divided into an octave with the rhyme scheme abbaabba, and a sestet that may vary in rhyme scheme. One example is Robert Frost's Design, which adheres to this form. The English sonnet, or Shakespearean sonnet, also consists of 14 lines in iambic pentameter, but is organized into three quatrains and a final rhyming couplet with the rhyme scheme ababcdcdefefgg. This form allows for a volta or turn in thought, commonly occurring between the third quatrain and the final couplet, marking a shift in the theme or argument of the poem. An example is Shakespeare's Sonnet 18, beginning with 'Shall I compare thee to a summer's day?'Both sonnet forms include a volta, although they appear at different points in the poem. The Italian sonnet typically places the volta between the octave and sestet, while in the English sonnet, it can occur either between the octets and sextets or before the closing couplet. Sonnets traditionally address themes such as love, beauty, politics, mortality, and nature.In terms of structure, an Italian sonnet is suited for developing a problem in the octave and providing a resolution in the sestet, while an English sonnet allows for more compartmentalized exploration of themes before the overarching resolution in the final couplet.