How does Matthew Arnold describe sounds and make use of sound devices throughout "Dover Beach" to reinforce his message?

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Lorraine Caplan eNotes educator| Certified Educator

In "Dover Beach," sound is a central element.  Arnold uses much imagery of sound as well as rhythm to great effect in this famous poem.  Let's look at some lines to examine some of these.

In the first verse, Arnold uses personification: 

Listen! you hear the grating roar
Of pebbles which the waves draw back, and fling, (9-10)
Pebbles cannot roar, but people can and do, and giving an inanimate object a human quality is personification. 
In this line, Arnold uses rhythm to give the feel of the rhythm of the waves as they hit the beach:
Begin, and cease, and then again begin, (12) 
Notice his use of commas in this line. These separate the words in a way that mimic the waves quite effectively.
In the following lines, music is evoked, with the uses of the words "cadence" and "note":
With tremulous cadence slow, and bring
The eternal note of sadness in (13-14).
In the second verse, the idea of sadness as a sound is extended:
Sophocles long ago
Heard it on the Ægean, and it brought
Into his mind the turbid ebb and flow
Of human misery; we
Find also in the sound a thought,
Hearing it by this distant northern sea (15-20).
Sophocles has heard "it," which means the waves, of course, but also the "note" of sadness, and in the next lines, the speaker hears the "thought" in the sound of the waves.
The third verse is concerned with sound as well:
But now I only hear
Its melancholy, long, withdrawing roar,
Retreating, to the breath
Of the night-wind, down the vast edges drear
And naked shingles of the world (24-28). 
The speaker hears again the "roar," which seems to be more of an inhalation than an exhalation, since it is "retreating" to the what seems like the quieter "breath of the night-wind," which give us a very concrete image of the wind against the shingles. 
In the very last verse, as the poem ends, there is more suggestion of sound,
Swept with confused alarms of struggle and flight,
Where ignorant armies clash by night (36-37).
"Confused alarms" and "clash by night" give us strong sound imagery, as the poem ends. 
So often when we think of imagery, we think of sight.  But Arnold has focused even more on sound imagery in this poem, and he does so quite successfully.  When we think of the sea, the sound of it is at least as important as how it looks to us, and the yearning and sadness he conveys through his sound imagery evokes the contemplative sadness that the sea does give us. 
thanatassa eNotes educator| Certified Educator

Matthew Arnold uses sound in two ways in "Dover Beach." The first is use of sound-related figures of speech, such as alliteration, assonance, and onomatopoeia. The second is his description of the sound of the waves.

In the first stanza we have a sequence of sounds that give the impression of the eternal cycle of the waves, with the tide ebbing and rising day after day. We see this effect in the first stanza in the word sequence: " ...grating roar ...waves draw ... cadence slow."

Next, Arnold also has extensive descriptions of the sounds of the waves and the pebbles on the shore in the poem. The terms in which the sound is described create meaning through a form of personification, or attribution of human qualities of emotion to inanimate objects. The sound of the waves is a "grating roar" and the waves "fling" pebbles, both impressing upon us the strength of the tides. However, despite this power, the sound is also a "tremulous cadence," which suggests perhaps the hymns and chanting of a religious service. This emphasizes that religion, which is at high tide, despite its visibility, is gradually withdrawing from the world in the modern era.