When I was a child I came home from yeshiva with a question my rebbe had asked us. Why is Joshua the son of Nun* (יְהוֹשֻׁעַ בִּן-נוּן, typically) called "bin Nun" rather then "ben Nun"? If we gave a good answer we could get a prize.
Dutifully I asked my father and he said he didn't know, but would check. He found that the Ramban (Ex. 33:11) suggested that the name is to be read together as "binnun" (as indicated by the masoretic hyphen) in the sense of בינון, Joshua, "the one with understanding."
My rebbe liked that answer, even though I doubt he believed I looked up the Ramban myself (being perhaps 9 years old).
For more than two decades I have thought about this enigmatic vocalization. Over the years I have collected other suggestions. The Chasam Sofer suggested that when Joshua's name was changed from Hoshea to Yehoshua there were no nekkudot for the yud, (which had been previously part of the name Sarai before a yud was removed and replaced with a heh, making Sarah [BT Sanhedrin 107a]) so two dots were "borrowed" from the segol under the "ben," leaving it with one dot, that is, a hirik. (What about Num. 13: 8 הוֹשֵׁעַ בִּן-נוּן?) Indeed, when I asked a great talmid chochom about the unusual vocalization he began his reply by saying "There is much Torah on this, but it is mostly derush."**
In fact, Joshua is not the only "bin" in Tanakh. Other examples include Deut. 25:2 (וְהָיָה אִם-בִּן הַכּוֹת הָרָשָׁע), Jonah 4:10 (שֶׁבִּן-לַיְלָה הָיָה וּבִן-לַיְלָה אָבָד), and a personal name: Proverbs 30:1 (אָגוּר בִּן-יָקֶה). Furthermore, another talmid chochom pointed out to me that it is possible that Benjamin, בִּנְיָמִין, is another example. Indeed, Rashi (Gen. 35:18) says that the meaning of the name is "son of the south," as in the expression צָפוֹן וְיָמִין, "north and south" (Psalm 89:13) which is to say that it is a contraction of two words. Given the vocalization וְיָמִין, evidently "ben" changes to "bin" in "Binyamin" for ease of pronunciation.
Paranthetically, a note about "ease of pronunciation" is in order. It's important to recognize that languages do funny things for the ease of pronunciation of its native speakers. Not being a native speaker is an impediment to understanding why this occurs. For example, in Hebrew the surrounding vowels determine whether the בגדכפת letters are hard or soft. Thus, you would say "Bereishit" but if you introduce the conjuctive "and," (ו) you would have to say "u-vereishit." This is correct Tiberian Hebrew. If you know the rules then you make the change. But am I wrong in suggesting that almost all of us would have no trouble at all saying "u-bereishit"? That's because the change does not occur to ease our own pronunciation. As non-native speakers of Tiberian Hebrew there is nothing difficult to our own ears and mouths that prevents us from reading it either way. Not so to native speakers who did have this difficulty.
To give a practical example in English. South of India there is a country called Sri Lanka. North of the Sinai desert there is a country called Israel. Americans pronounce "sri" like "shri." Americans pronounce "Israel" like "Izreal." Natives of Sri Lanka pronounce it "ssri," and Israelis pronounce it "Yissrael." Why don't Americans call Sri Lank "Ssri" Lanka? Why don't they call Israel "Issrael?" The answer is because those are too difficult for Americans to pull off. There is no "ss" followed by an "r" in English (which is why all you Srulis out there have to endure "Shruli"). Americans just can't say "Ssri," so they say "Shri." In American English the consonant /s/ is often voiced as if it were a z, depending on the vowels around it. It is difficult for Americans to say "Iss," but not "Iz." As for "ra-el," fuggedaboutit. Are you kidding me? These two syllables go together like oil and water in English (not so Hebrew) so Americans say "real." "Izreal."
But I digress. My point was that evidently--at least it is possible--there is something about the conjunction "Ben-Yamin," Bnymyn, which required "Binyamin" instead of "Benyamin" (seems like we do it fine in English, don't we?). Perhaps this is somehow the case with יְהוֹשֻׁעַ בִּן-נוּן and the other examples.
The aforementioned first talmid chochom who pointed out that most of the "Torah" on the subject is derush noted that "Grammar may be more useful here":
Shen (tooth) and ben (son) are pronounced with a tzere in the absolute state, yet appear as shen (with a segol) and ben (with a segol) in the construct state. In the plural construct, we find shinnei (also: 'et [time] and 'ittei), with a dagesh in the second root letter. One suspects that the double nun in bin-nun acts exacly like the double nun in shinnei.
Awhile ago Steg said something similar. He pointed out that "bin Nun" works as a unit, that is, a geminated (double) nun. He gave an example based on the Hebrew word lêv (heart). In semikhut it is lev and with suffix it becomes libb-. Perhaps it is the same thing with "son." Bên, Ben and Binn-.
Indeed, the masorah combines bin and Nun: bin-Nun (the hyphen indicates that it is to be regarded as one word).
Bottom line: one has to explain the oddity of this and the few other examples. It would be easier to explain if not for the others, particularly the personal name אָגוּר בִּן-יָקֶה in Proverbs!
All this leads one to suspect that one is dealing with an old oral tradition. The question as to what the Tiberian massoretes were doing has been much discussed. Although one is tempted at the outset to assume that they were merely recording traditions, one wonders how indeed there were millions of minute traditions regarding the Biblical text. Furthermore, earlier evidence whether from the Talmud or elsewhere shows that Hebrew was pronounced differently at different times. It is clear that at the same time the Jews of Babylon pronounced Hebrew differently. Thus, it is practically impossible to say that the Tiberians recorded the way the Bible was read from time immemorial in all its exactitude. If so, what were they doing? Were the Tiberians recording their own pronunciation (using old traditions [kri u-kesiv, small letters, etc.]), of course)?
That might seem compelling. Indeed, one of the great Bible scholars of last century, Paul Kahle, believed that the Tiberians were compiling an idealized way of reading the Bible, perhaps modeled on (or at least parallel with) a similar effort for the vocalization of the Qur'an at roughly the same time. Kahle believed that he had proof that the Qur'an was originally consonantal and at a certain point in time it was vocalized according to one way of reading Arabic: the way that the Quraysh tribe of Mecca spoke Arabic (Muhammad was a Qurayshi). This tribe's pronunciation was romanticized as the ideal Arabic, and the consonants of the Qur'an were made to conform with this pronunciation.
An interesting excerpt from Paul Kahle's great (but not infallible) The Cairo Genizah on precisely this subject can be had here: link
Of particular relevance is his view, as follows:
Kahle's view has been justly criticized on the grounds that is is plainly difficult--if not ludicrous--to suggest that the massoretes consciously changed anything. Indeed, they must have done nothing but record what they believed to be the tradition. In cases of doubt they had recourse to solutions, like the halakhic principle of following the majority, of chasing down more authentic (it would seem) traditions, etc. But in the main it would seem difficult to posit an intentional language revolution, as Kahle suggests.
What of the Muslims who, too, should have venerated their Qur'an? If so, how could they have subjected it to modification to conform with the Quraysh pronunciation of Arabic--if indeed this was something more than a minor modification? I would suggest two things. One is that the Muslims did not believe they were dealing with an extremely ancient text with an extremely ancient tradition of pronunciation. Their's was only a couple of centuries old. In contrast, the Jews believed they were dealing with sacred texts that were as much as 2000 years old! Furthermore, at the time the Muslims were in a period marked byijtihad, a sort of interpretive renaissance in which all sorts of Islamic practices, beliefs and traditions were subjected to a process of scrutiny with the aim of establishing authenticity. Such a project would have been par for the course in such a time (believed to have ended at the end of the 10th century). At least as far as we know, no specific parallel occurred among the Jews. Although this period, the time of the Ge'onim, was marked by creativity and even renewal, it was also a period of consolidation, a period where the Talmud was fixed on a pedestal, where the idea of sof hora'ah was fixed. It seems unlikely that in this period the Jews, even an elite in Tiberias, were tinkering with the pronunciation of Hebrew as opposed to recording it, or at least believing that is all they were doing.
In any event, what I think is most plausible is that these fine listeners, these men with sensitive ears, definitely heard "bin Nun (or "binnun") and most certainly not "ben Nun!" That is how it was pronounced. Why did they hear this? What is it's origin? I am still looking...
* The "u" of "Nun" is to be pronounced like the short "oo" in "wood;" "noon," except rhymes with wood and not "afternoon."