Here's how each word contributes:
* Weary: This word suggests exhaustion, both physically and emotionally. The speaker is tired of his grief and the memories of Lenore. This weariness adds to the overall sense of despondency.
* Dreary: This word emphasizes the dull, monotonous, and depressing nature of the speaker's surroundings and state of mind. The dreary atmosphere amplifies the speaker's isolation and hopelessness.
* Bleak: This word conjures up images of barrenness and desolation, further reinforcing the oppressive and somber mood. It suggests a lack of hope and any chance of happiness.
These words, along with other similarly evocative vocabulary choices throughout the poem, create a powerful and pervasive sense of darkness and despair. They contribute to the overall gothic atmosphere of the poem and emphasize the speaker's descent into madness and despair as he grapples with his grief and the ominous presence of the raven.