וַיְשַׁמַּ֤ע שָׁאוּל֙ אֶת־הָעָ֔ם וַֽיִּפְקְדֵם֙ בַּטְּלָאִ֔ים מָאתַ֥יִם אֶ֖לֶף רַגְלִ֑י וַעֲשֶׂ֥רֶת אֲלָפִ֖ים אֶת־אִ֥ישׁ יְהוּדָֽה׃
Saul mustered the troops and enrolled them at Telaim: 200,000 men on foot, and 10,000 as Judah’s contingent.
(The above rendering comes from the RJPS translation, an adaptation of the NJPS translation. Before accounting for this rendering, I will analyze the plain sense of the אִישׁ term, by employing a situation-oriented construal as outlined in “Notes on Gender in Translation,” pp. 11–16.)
On the “collective” usage of the singular אִישׁ in the context of hostilities, see my comment to Judg 7:23. Here, such usage profiles the referent more precisely as a distinct entity within a larger military force. See further my comment at Judg 7:24.
In this case, the syntax is unusual—featuring the resumptive use of an accusative (direct-object) marker: וַעֲשֶׂרֶת אֲלָפִים אֶת־אִישׁ יְהוּדָה. This can be construed as informative per Biblical Hebrew Reference Grammar (2017), §33.4.2(2), citing Bekins 2014: it signals that “the information status of the object is high within the discourse structure, specifically, ... the object is identifiable, animate, and persistent within the context.” In other words, the referent of אִישׁ יְהוּדָה is treated as a distinct collective entity; אִישׁ is not being used as a mere counting unit. (So also LXX: καὶ τὸν ιουδαν, versus the usual ἄνδρες for counting; and Targum: יָת אְנָשׁ יְהוּדָה, versus the usual גֻברָא for counting.)
As for rendering into English, the NJPS ‘10,000 men of Judah’ nowadays places undue emphasis on masculinity. (The fact that women are not in view can go without saying, because it is self-evident from the military context.) Furthermore, it relies upon an archaic sense of men as participants. Worst of all, it misses the situational nuance described above. On more properly rendering the Hebrew term into idiomatic English, see my comment at Josh 10:24.