* Evasive and indirect descriptions: Initially, Alicia's illness is described vaguely. Quiroga avoids clinical terminology, opting for phrases like "a strange malaise," "a gradual weakening," and "a growing pallor." This ambiguity heightens the sense of unease and mystery surrounding her condition. The reader is left to infer the severity of her situation, mirroring the uncertainty and helplessness of those around her.
* Sensory details that hint at the supernatural: Instead of focusing on purely physical symptoms, Quiroga uses sensory details that hint at a more sinister origin. The feather pillow itself becomes a potent symbol, described with evocative language emphasizing its softness yet also suggesting a lurking threat: "the soft, yielding down of the pillows." The descriptions of her room, particularly the shadows and the unsettling quiet, contribute to the overall atmosphere of dread.
* Increasingly vivid and disturbing imagery: As Alicia's condition worsens, the language becomes more graphic and disturbing. The descriptions of her physical decline become more precise, focusing on the pallor of her skin, the darkening of her eyes, and the wasting away of her body. These descriptions are carefully chosen to highlight the unnatural and unsettling aspects of her deterioration, fueling the reader's sense of horror. The use of words like "cadaverous" and "emaciated" emphasize the horrifying nature of her decline.
* Metaphor and symbolism: Quiroga uses symbolic language to suggest the draining of Alicia's life force. The gradual disappearance of her blood, alluded to throughout the story, is a powerful metaphor for her fading vitality. The feather pillow itself becomes a powerful symbol of the unseen, malevolent force draining her life.
* Shift in tone: The initial tone of the story is one of quiet observation, almost detached. However, as Alicia’s condition worsens, the tone becomes increasingly tense and foreboding. The language reflects this shift, becoming more charged and emotionally intense.
In essence, Quiroga masterfully uses language to create a slow, creeping sense of dread. By avoiding explicit descriptions and employing carefully chosen imagery and symbolism, he builds suspense and allows the reader to experience the unsettling nature of Alicia's decline on an emotional and visceral level. The language itself becomes a tool for psychological horror, far more effective than mere clinical description.