Alliteration
The repetition of an initial sound in different words, usually a consonant-is a common technique. It depends on our recognition of the similarity of certain sound-sounds which on close inspection may not be very similar at all, but which we, as speakers of English, have agreed will be classed alike, for example, the initial "t" of "toil" and "t" after "s" of "West". Test this difference by holding your hand before your mouth when you say these two words. Because we have agreed to use the single symbol "t"'for these two sounds, we indicate that we are not aware of the difference of sound. To us, they are functionally similar, even though the correspondence between written symbol and spoken sound is frequently unreliable. In reality, sounds that we think of as identical sounds are only a class of similar sounds. Within the similarity of sounds arranged as alliterative pairs here by Hopkins, there is a great deal more variety than we may frist suspect. The initial sounds in "trade" actually resembles"ch" many speakers, because of the following "r". Contrast this with the clear "t" of "toil".
Since rhyme and metre are traditional elements of the sonnet form, the extensive use of alliteration in this poem is its most unusual formal feature. In only one line (5) in there no alliteration, and there are numerous instances of double sets of alliteration, and also of multiple alliteration: the world is charged with the grandeur of god.