Final answer:
Anglo-American sonnets like the Shakespearian, Petrarchan, and Spenserian, are distinguished by their 14-line structure, specific rhyme schemes, and the presence of a volta, which signifies a turn in thought.
Step-by-step explanation:
The distinguishing features of notable Anglo-American sonnets include specific structural and rhyming patterns. A Shakespearian sonnet typically consists of 14 lines in a 4+4+4+2 structure with an ABAB CDCD EFEF GG rhyme scheme and a volta, or turn in thought, occurring between the octet and sextet or before the final couplet. The Petrarchan sonnet, often used by Italian poet Petrarch, has 14 lines as well but is divided into an octet with an ABBAABBA rhyme scheme and a sextet with varying rhymes, with the volta between the stanzas. The Spenserian sonnet, developed by Edmund Spenser, modifies the Petrarchan form by following the ABAB BCBC CDCD EE rhyme scheme.
There's flexibility within these structures for poets to express their views on love, life, or other themes. Notable examples include Shakespeare's sonnets, which are often likened to passionate love letters, and Robert Frost's use of the Petrarchan sonnet in "Design." The sonnet form was also embraced by Modernists like Edna St. Vincent Millay, contrasting their work from contemporary poets such as Eliot and Williams who favored more free-form styles.