What is the importance of the musicality of the rhythm in "The Raven"?

One of the reasons why this poem is so incredibly well
known and famous is the way that it is almost song-like in its rhythm and music. It can
be compared to many songs because of its evocative rhythms, alliteration, rhymes and
other sound effects that make it memorable. Remember that unless we hear poetry we are
often not able to fully comprehend what the poet is really doing through the sound of
the words and their rhythm.

In particular what
is notable in this poem is the use of internal rhyme, or rhyme that occurs within the
lines or repetition of an end rhyme within a line. For some examples of this, consider
how "dreary" is rhymed with "weary" in line 1 and then "napping," "tapping," and
"rapping" in lines 3 and 4. Likewise alliteration and onomatopoeia is combined in a
somewhat exaggerated but definitely striking manner. Consider the following
line:

What
this grim, ungainly, ghastly, gaunt, and ominous bird of
yore...

The repetition of the
"g" sound which combines onomatopoeia with alliteration to great effects serves to
reinforce the grim appearance of the raven.

All of these
examples help to create this remarkable and intensely memorable poem through the
production of what can be termed word-music, because so many effects are used that in
many ways this poem is similar to a song.