OET interlinear JOB 39:18

uW Translation Notes:

Note 1 topic: grammar-connect-logic-contrast

כָּ֭⁠עֵת בַּ⁠מָּר֣וֹם תַּמְרִ֑יא

(Some words not found in UHB: about,time on,height spreads_~_wings laughs to,horse and,to,rider_of,its )

Yahweh is implicitly drawing a contrast between the apparently foolish behavior of the ostrich as a mother and its impressive physical capabilities, specifically how fast and powerfully it can run. If it would be helpful to your readers, you could indicate the contrast explicitly in your translation. Alternate translation: [Nevertheless, when it lifts itself on high]

Note 2 topic: figures-of-speech / idiom

כָּ֭⁠עֵת בַּ⁠מָּר֣וֹם תַּמְרִ֑יא

(Some words not found in UHB: about,time on,height spreads_~_wings laughs to,horse and,to,rider_of,its )

This expression does not refer to the ostrich flying, since ostriches cannot fly. Rather, it is a reference to what an ostrich does in order to run. It stretches to its full height and spreads and flaps its wings. If it would be helpful in your language, you could state the meaning plainly. Alternate translation: [Nevertheless, when it runs]

Note 3 topic: figures-of-speech / personification

תִּֽשְׂחַ֥ק לַ֝⁠סּ֗וּס וּ⁠לְ⁠רֹֽכְבֽ⁠וֹ

(Some words not found in UHB: about,time on,height spreads_~_wings laughs to,horse and,to,rider_of,its )

Yahweh is speaking of the ostrich as if it could consciously express by laughing what it was thinking and feeling. Here the term laughs implicitly means laughing scornfully. The ostrich would express scorn towards a horse and its rider because it could run faster than the horse. If it would be helpful in your language, you could state the meaning plainly. Alternate translation: [it can run even faster than a horse]