Alliteration is a literary device that refers to the use of the same consonant word in consecutive words in a sentence. In other words, we can say that alliteration is when the same consonant sound in close proximity in a sentence.
In the given sentence from "Wuthering Heights" by Emily Bronte, the author/ speaker uses the figurative language of alliteration. Alliteration is seen/used in the words <em>"knocking my knuckles"</em> and<em> "fingers closed on the fingers . . ."</em>
Subtext, by definition, refers to what one might call "reading between the lines". it's a deeper meaning behind the way a character may act or even the tone in which they speak.
