Prior to chapter five of Mary Shelley's Frankenstein, Victor is very excited about the being he is about to reanimate with life. All of chapter four is spent defining, in great detail, the exhaustive extent Victor went through to insure the success of his experiment and the blessing he would receive from his "son." Throughout the chapter, Victor's language is overwhelmingly positive.
A new species would bless me as its creator and source; many happy and excellent natures would owe their being to me. No father could claim the gratitude of his child so completely as I should deserve theirs.
Essentially, Victor exhausted every means he had to choose each part for his "son." He was meticulous in defining how the parts were put together, even the tiniest veins.
It is in chapter five where Victor’s dismay and horror are seen. The creature he had worked relentlessly upon was horrifying.
How can I describe my emotions at this catastrophe, or how delineate the wretch whom with such infinite pains and care I had endeavored to form? His limbs were in proportion, and I had selected his features as beautiful. Beautiful!—Great God!
Instead of being overjoyed at his success, Victor's language shows his utter disappointment. His creature is not beautiful--the pieces he chose did not come together to result in the beautiful being he desired. Instead, the dreamt beauty is shattered upon the opening of the creature's eye.
Essentially, Victor’s language leaves nothing to the imagination about his feelings. Readers are very aware of Victor's horror and dismay. Therefore, the importance of Victor’s language lies in the fact that nothing of his emotion is hidden from the reader. Instead, readers are very aware of Victor’s horror at his "son."