banquet
讌 centers on a formal feast or banquet, typically involving speech and celebration.
讌 combines 言 (speech) with 燕, which likely contributes the sound and may relate to the idea of a feast or banquet. The exact historical development is uncertain.
The left side 言 (speech) suggests talking, and the right side 燕 looks like a bird over fire, evoking a roasted bird at a feast. Together they paint a scene of a banquet with lively conversation.
For エン, picture the banquet ending with everyone saying 'en' as they toast: 'en' -> エン, the sound of a satisfied feast.