yom huledet

The Hebrew phrase for "birthday" is יום הולדת yom huledet. While it's certainly a familiar phrase, it's actually kind of a strange construct. Huledet is the hufal (passive and causative) form. Why not use the simpler יום הלידה yom haleida - "day of birth"?

The phrase yom huledet appears three times in the Bible. The first is in Bereshit 40:20 after Yosef deciphered the dreams of his servants (the other two are in Yechezkel 16:4,5). Here is how the phrase appears in Bereshit:

וַיְהִי בַּיּוֹם הַשְּׁלִישִׁי יוֹם הֻלֶּדֶת אֶת־פַּרְעֹה וַיַּעַשׂ מִשְׁתֶּה לְכָל־עֲבָדָיו וַיִּשָּׂא אֶת־רֹאשׁ שַׂר הַמַּשְׁקִים וְאֶת־רֹאשׁ שַׂר הָאֹפִים בְּתוֹךְ עֲבָדָיו׃

On the third day—his birthday [yom huledet]—Pharaoh made a banquet for all his officials, and he singled out his chief cupbearer and his chief baker from among his officials. 

On this verse, Rashi asks our question above, and mentions the other occurrences of  yom huledet:

יום הלדת את פרעה. יוֹם לֵידָתוֹ, וְקוֹרִין לוֹ יוֹם גֵּינוּסְיָא. וּלְשׁוֹן הֻלֶּדֶת, לְפִי שֶׁאֵין הַוָּלָד נוֹצָר אֶלָּא עַל יְדֵי אֲחֵרִים, שֶׁהַחַיָּה מְיַלֶּדֶת אֶת הָאִשָּׁה, וְעַל כֵּן הַחַיָּה נִקְרֵאת מְיַלֶּדֶת, וְכֵן וּמוֹלְדוֹתַיִךְ בְּיוֹם הוּלֶּדֶת אוֹתָךְ (יחזקאל ט"ז) וְכֵן אַחֲרֵי הֻכַּבֵּס אֶת הַנֶּגַע (ויקרא י"ג), שֶׁכִּבּוּסוֹ עַל יְדֵי אֲחֵרִים:

יום הלדת את פרעה HIS (PHARAOH’S) BIRTHDAY. It is called (Avodah Zarah 10a) “The birthday festival”. The causative passive form (הלדת) is used because the infant is born only by the assistance of others, for the midwife delivers the woman. On this account a midwife is called מילדת a Piel form “one who brings to birth”. This passive form occurs similarly (Ezekiel 16:4) “And as for thy nativity, in the day thou wast born (הולדת אתך)”. A similar passive form is used in (Leviticus 13:55) “after the plague (הכבס) is washed away”, because the washing is done by others). 

In other words, a better translation for yom huledet would be "the day [he] was delivered" instead of "birthday," even though both phrases refer to the same date. (An alternate suggestion, by Radak and Rabbeinu Bachye, is that this was the day a son was born to Pharaoh.) This can also help us understand why the phrase is yom huledet et paro, where Pharaoh is the object of the phrase, instead of yom huledet paro, which is how we would say it today. Pharaoh was the object - he was delivered on that day. According to this article, the verse describes the historical record of  "a ceremony at which the Pharaoh was born again as far as Egyptian protocol was concerned." 

So this usage could explain why yom huledet is the phrase we use for "birthday." However, there are other phrases used to describe birthdays in the Bible:

  כְּיוֹם הִוָּלְדָהּ k'yom hivalda - "as on the day she was born" (Hoshea 2:5)

 מִיּוֹם הִוָּלְדוֹ - m'yom hivaldo - "than the day of his birth" (Kohelet 7:1)

And in the mishna (Avoda Zara 1:3), we find yom haleida יום הלידה. 

So why didn't any of the above become the standard term for "birthday"?

I couldn't find an proven answer to this question. However, it seems that birthdays weren't a big deal in Judaism until recently. And so there wasn't need for a standard Hebrew phrase for the concept. I didn't find yom huledet mentioned in Rabbinic sources that weren't discussing the verses in Bereshit or Yechezkel until relatively recently.

We can see the trends even better, by looking at this chart of appearances of the phrase yom huledet (with both spellings) in Hebrew books over the last few centuries:

 

The usage (of the full spelling) really starts spiking around the 1960s. I assume that most of the earlier occurrences were discussing the biblical examples.

But as we saw, there were other choices - yom hivaldo or yom haleida. Why not them? My guess is that people were very familiar with the yom huledet of Pharaoh, due to the weekly Torah reading. And although Rashi gives it a slightly different explanation than "day of birth," that wasn't enough to prevent it from becoming the popular phrase.