Question about עָתִיד מְקֻצָּר and ו׳ הַהִפּוּךְ in Biblical Hebrew

Question

I’m a native Hebrew speaker, but only recently did I read a bit more in depth about how עתיד מקוצר works. So I noticed that, for example, the verb [יִבְכֶּה becomes יֵבְךְ](https://hebrew-academy.org.il/2017/09/25/יהיה-יהי-או-יהא-זאת-השאלה), but [יִבְנֶה becomes יִבֶן](http://web.macam98.ac.il/~litami/revitalilana/dd.htm): the vowel on the אית״ן letter is different (medium-length צֵירֶה in the former, short חִירִיק in the latter), and the latter gets an epenthetic vowel. In addition (as the latter link shows), יִרְאֶה becomes somewhat of a mix between the two: יֵרֶא, which has a medium vowel *and* an epenthetic vowel. Arguably it makes more sense than יִבֶן, which has a (generally disallowed) stressed short vowel, but still the system looks very confusing in general. How does this work? Does this have to do with the fact that there are sonorants in the latter two (/n/ in יבנה, /r/ in יראה), maybe? Also, what type of שְׁוָא are those in those forms? In addition, the latter link above displays some interesting pecularities regarding the form with ו׳ ההיפוך. Somehow, in יִרְאֶה, the vowel on the אית״ן letter changes from its original חיריק to a פַּתָּח, and there is no epenthetic vowel—but [there is one in וַיֹּאמֶר](https://hebrew-academy.org.il/2015/07/30/ו-ההיפוך) (cf. יֹאמַר). The verb יִבְכֶּה, on the other hand, [retains the same structure as its עתיד מקוצר form: וַיֵּבְךְ](https://cse.google.com/cse?cx=003922636974222575695%3Adxq675sw--g&ie=windows-1255&q=%E5%E9%E1%EA&hq=inurl%3A%2Fi%2Ft%2F&sa=+%E7%F4%F9%21+). What are these alterations based on? Even stranger: the second link provides the ו׳ ההיפוך equivalent of יִבְנֶה as וַיְבֶן—an epenthetic vowel and a שְׁוָא נָע! How do you even pronounce that? Which syllable would you stress? Or maybe it was just a mistake by the author and it should be וַיִּבֶן, as [this source](https://safa-ivrit.org/history/vav.php) gives the nearly identical וַיִּפֶן? תּוֹדָה רַבָּה מֵרֹאשׁ לְכֻלְּכֶם!

Answer 1

Well, if native Hebrew speakers have issues, what hope is there for the rest of us? Kidding. Partially.

You're examining the fine points. Why?