Hannah’s time in the sanctuary presents a deeply intimate moment of a soul pouring itself out to God. Her prayer was so unusual for its time that it led to a profound misunderstanding by Eli the priest. The primary approach among commentators is that Hannah prayed in a quiet whisper, as if speaking directly into her own heart. She wanted to keep her words completely private, ensuring no one else could hear her [מצודת ציון, מצודת דוד, ביאור שטיינזלץ]. Beyond this outward silence, her method of prayer showed immense emotional intensity [רד"ק]. She was speaking directly to God alone, completely bypassing any need for a human mediator [מלבי"ם].
Taking a more physical approach to her speaking to her heart, another perspective suggests she was actually praying about the organs located over her heart. She presented a plea to God based on the idea that every part of the human body was created for a specific purpose. Just as a woman's breasts were designed to nurse a baby, she asked God to give her a child so they could fulfill their natural function [צאינה וראינה].
As she prayed, her lips were moving, yet she made no audible sound [מצודת ציון]. This specific behavior caused Eli to mistakenly conclude that she was drunk. During that period in history, silent or whispered prayer was not the norm [רש"י]. The sheer length of time she spent praying in this unheard manner seemed completely unreasonable to him [מלבי"ם]. Furthermore, moving one's lips without producing sound, or muttering to oneself, are classic signs of intoxication. Seeing her mouth moving silently, Eli naturally assumed she was under the influence of wine [מצודת דוד, ביאור שטיינזלץ].
A deeper explanation for Eli's error suggests that he actually experienced a partial flash of divine inspiration. Through prophecy, Eli sensed that Hannah was making a vow to dedicate her future son as a Nazirite, a spiritual status that requires strict abstinence from wine. Because wine is known to lead to sin, a person who witnesses the negative effects of intoxication is encouraged to distance themselves from it. Eli connected these prophetic fragments incorrectly. He assumed that Hannah was currently drunk, and out of regret for her own shameful state, she was vowing to keep her future son away from wine [אהבת יהונתן].