Final answer:
An Italian sonnet is a fourteen-line poem written in iambic pentameter with a fixed form, while an English sonnet has a different structure. The octave of an Italian sonnet has a rhyme scheme of abba abba, while an English sonnet consists of three quatrains and a concluding couplet.
Step-by-step explanation:
An Italian sonnet is a fourteen-line poem written in iambic pentameter with a fixed form. It consists of an octave (a stanza of eight lines) and a sestet (a stanza of six lines). The rhyme scheme for the octave is typically abba abba. In contrast, an English (or Shakespearean) sonnet is also a fourteen-line poem written in iambic pentameter, but it is composed of three quatrains (stanzas of four lines) and a concluding couplet. The rhyme scheme for an English sonnet is abab cdcd efef gg. While both sonnet forms share the fourteen-line structure and iambic pentameter, their distinctive rhyme schemes and stanzaic arrangements distinguish the Italian and English sonnets.