swallow
嚥 centers on the physical act of swallowing, moving something from the mouth down the throat.
嚥 combines 口 (mouth) with 燕, which likely contributes the sound エン and may have originally depicted a swallow (bird) with an open mouth, reinforcing the swallowing meaning.
The mouth 口 on the left and the swallow-bird 燕 on the right suggest a bird using its mouth to swallow food. Picture a swallow gulping down an insect.
For エン, imagine the swallow bird making an 'en' sound as it swallows: en -> エン, and the mouth closes around the food.
swallowing; deglutition
aphagia; aglutition; acataposis
dysphagia (symptom of difficulty in swallowing); dysphagy
presbyphagia
breathing in (of a foreign body, food, etc.); pulmonary aspiration; mis-swallowing; swallowing down the wrong pipe
aspiration pneumonia