OET interlinear YOEL (JOEL) 2:16

uW Translation Notes:

Note 1 topic: figures-of-speech / merism

קִבְצ֣וּ זְקֵנִ֔ים אִסְפוּ֙ עֽוֹלָלִ֔ים וְ⁠יֹנְקֵ֖י שָׁדָ֑יִם

assemble elders gather children and,sucking_children_of (Some words not found in UHB: gather people sanctify congregation assemble elders gather children and,sucking_children_of breast leave bridegroom from,room_of,his and_[the],bride from,chamber_of,her )

Joel is speaking of two things in order to mean those two extremes and everything in between. If it would be helpful in your language, you could use an equivalent expression or plain language. Alternate translation: [assemble people of all ages]

Note 2 topic: figures-of-speech / explicit

יֵצֵ֤א חָתָן֙ מֵֽ⁠חֶדְר֔⁠וֹ וְ⁠כַלָּ֖ה מֵ⁠חֻפָּתָֽ⁠הּ

leave bridegroom from,room_of,his (Some words not found in UHB: gather people sanctify congregation assemble elders gather children and,sucking_children_of breast leave bridegroom from,room_of,his and_[the],bride from,chamber_of,her )

Joel means implicitly that while newlyweds are ordinarily excused from public duties, this is an exceptional circumstance that calls for even their attendance. Alternate translation: [Even newly married men and women should come to the assembly under these exceptional circumstances]