What does 1 Samuel 1:12 mean?

Hannah has been described as deeply distressed and weeping bitterly (1 Samuel 1:10). She is so distraught because she is barren and her husband's second wife purposely provokes her (1 Samuel 1:6–8). She is praying fervently to the Lord and taking a vow before Him in the temple, offering to give any son He would grant to her back to Him in service for the rest of the boy's life (1 Samuel 1:11).

When Hannah arrived, Eli, the priest, had been sitting on a special chair by the doorpost (1 Samuel 1:9). Israelite priests were all descendants of Aaron, the brother of Moses (Exodus 28:1–5, 40–43; Numbers 3:3). At this time, what we think of as the temple had not yet been built (1 Kings 6). The center of worship, namely the tabernacle and its contents (Exodus 25—31; 35–40), was in Shiloh (Joshua 18:1). Given the descriptions of Eli (1 Samuel 2:11, 27-36), he seems to be the high priest. As such, he is responsible for the other priests and entrusted to represent the people before God through things like the yearly sacrifice on the Day of Atonement. Now Eli notices Hannah praying and watches her. He sees her lips moving, probably very quickly and intently, but no sound is coming out (1 Samuel 1:13). This doesn't look right to him (1 Samuel 1:14).