Rashi to Devarim 1:5 says Moshe translated the Torah into 70 languages. Why did he do so?
The Kesav Sofer answers that there were people who where saying that the Torah is only for when we are amongst ourselves, in the desert, or in Eretz Yisroel. Therefore, before they entered Eretz Yisroel it was written in all the languages, telling the Jews that no matter where you go, and no matter what language you speak, the Torah applies in all of them. The Kedushas Levi points out here that the Torah has many foreign words from the African languages to the Greek language. He says that this is because the source for the foreign nations are on High, and in order for them to exist on the physical plane they must exist on the metaphysical plane in the Torah. He takes the original point one step further, and says the Jews born out of Israel will see that their native language is in the Torah, and this will be a source of encouragement for them, as they will see something to identify with.
The Ksav Vhakabalah has a completely different approach. He says that the Seventy languages taught here are the equivalent of the language of the Gemara of Lishnah Achrinah. That is, a different Pshat that Moshe taught the Jews that there are 70 ways to learn the Torah, and none of them is wrong or right. That was important at this point as he was leaving, and this was an important thing to explain before he left the world.
The answer by SimchasTorah is depressing. "Hey Moshe, why are translating the Torah before we settle the land?"
"Oh because you're going to get kicked out, scattered all over the world, and lose your native language." Ktav Sofer. "But don't worry. Take solace in your future exile because all languages come from Hebrew." Kedushat Levi (but please see the reference in full), apparently a reference to Edenics. "Wow, so we kept Hebrew in Egypt, but this exile will be so terrible that we'll lose even that?"
I actually stumbled across this Baal Haturim yesterday on Devarim 6:4 and why the ayin was large. He writes:
עי''ן דשמע גדולה שע' שמות יש לישראל ונתן להם תורה שיש לה ע' שמות ונדרשת בע' פנים להבדיל בין ע' עכו''ם.
Basically, ayin has the value of 70 which alludes to the 70 names of Israel and the Torah and the 70 faces which the Torah is interpreted relates to the 70 nations. Seemingly, this connects all the above thoughts.
Rashi says on Devarim 1:5 and 27:8 that Moshe explained the Torah in seventy languages. Shabbat 88b and Midrash Rabbah to Shemot 5:9 explain that the "thunderings" plural refer to the word of Hashem from Har Sinai splitting into 70 tounges like many sparks come from a hammer.
Rashi on Devarim 27:8 says that Moshe wrote the Torah on stones in 70 languages. I think stele would be a better English word, like the Rosetta stele. This would support the Ramban who writes that the stones were gigantic. This is my idea on it, because we have other stones like the Code of Hammurabi and other contemporary laws that are Mosaic sounding. In Avodah Zara 2b, it says that Hashem went to the 70 nations (through messagers? perhaps through each of the previous 26 generations) to offer the Torah first but all the nations refused because of one mitzva or another they couldn't accept until He came to Israel last. See Rashi (citing Sifrei Devarim 343:6; Avodah Zarah 2b), Tur HaAroch (citing the Ramban) on Devarim 33:2; Targum Yerushalmi loc. cit.; Targum Yonatan loc. cit.; Sifri, beginning of Ve-zot Ha-Bracha, Mekhilta, BT AZ 2b, Eichah Rabbah 3, Pirkei D’Rabbi Eliezer ch. 41. Also note here that each nation relates to Hashem by a particular sefirah. However, we see their culture (as Rabbi Tzadok of Lublin emphasizes) didn’t last.
But that means all the nations knew of the Torah but interpreted it their own way as we see in archæology wherein some are supposedly carbon-dated before Har Sinai. This still leaves the question that Gentiles don't have to follow the Torah proper. As far as the 7 Noachide laws go, which pre-date the Torah below to a certain extent, they are expounded on only by the Torah and Oral Law such as when a goy is liable for what. The 70 languages, then, explains why Moshe had to set them straight.
ח,ה ר' יהודה אומר על אבני [המזבח כתבום אמרו לו] האיך למדו [אותם] עובדי כוכבים את התורה אמר [להם] מלמד שנתן [המקום] בלב כל אומה ומלכות והשיאו את הכתב מגבי האבנים בשבעים לשון באותה שעה נתחתם גזר דינן של עובדי כוכבים לבאר שחת ר"ש אומר על הסיד כתבו כיצד כידוהו וסידוהו בסיד וכתבו עליו את כל דברי התורה בע' לשון וכתבו [מלמטה] (דברים כ) למען אשר לא ילמדו אתכם וגו' אם אתם חוזרין בכם אנו מקבלין אתכם.
This shows that the nations knew of Noachide prohibition against idolatry from the interpretations of Torah via the languages. Ibn Ezra (citing Rav Saadia Gaon) writes that these stelai had the overall count of mitzvot and prohibitions like those recorded in Halachot Gedolot. That way the nations could copy it down. See the Ein Yaakov on Sotah 7:16. While there are many problems with teaching Gentiles Torah, see Contemporary Halachic Problems, Vol. 2, Pt. 2, Ch. XVI, this can be easily resolved by teaching them the Torah and Oral Law as it relates to the Sheva Bnei Noachide laws.
As far as the 70 interpretations, I think this is more of a reference to the Sod (gematria of 70) of Torah rather than davka interpretations. Ateret HaMikra (citing Aggadat Bereishit 15:1). That's because there are actually 98 interpretations (which mitigate the 98 curses?), each halachah explained with 49 reasons to rule a matter one way and 49 reasons to rule the opposite. Yerushalmi, Sanhedrin 4:2, 22a. I'm assuming that ma'aseh hu haikar and that the Torah is not just folk tales. Accord Rabbeinu Bachya on Devarim 1:5. Rather, the 70 facets are the 70 languages the Sanhedrin knows. HaKtav vehaKabbalah (citing the Raya Mehemna)(q.v.). The High Court reveals the secrets of a matter, they bring the hidden truth to light. A more literal yesh m'ayin. These (lime?)stones were erected by Yehoshua in Gilgal as is written in his eponymous sefer, 4:9 & 20, in which the letters were engraved in the plaster. 8:32. And Gilgal was also where the first proto-Temple was.
In this sense, translation is interpretation. In an interview with R' Robert Alter who recently finished his translation of the Tanach, he says:
Every great work of literature – and there’s much great writing in the biblical Hebrew – has a mastery of means in its own language. It’s not only the kind of perfect word choice and subtle shifts from one level of the language to another, but also the rhythms, the lengths of words, etc. When you’re translating, you can’t possibly get all of those, while all the different features come together in perfect harmony in the original language. In most cases, you decide what’s less important and you sacrifice something: maybe you don’t focus on the order of the words in order to achieve some other effect of the original that’s important; maybe I can get the rhythm of the language but not quite the English equivalents that have the exact same resonance as the original.
So too in the JPS Commentators' Bible, they retained both the 1917 and 1985 JPS translations because the former is more literal and the latter more free-flowing.
Plus, each languages has its own nuances in how they relate to Hashem. Accord Kedushat Levi on Devarim 1:5(explaining why we find Aramaic, Greek, and Afrikaans, so that Gentiles will be familiar with the Torah). [Personally, I think this Kedushat Levi is anachronistic. Originally, the world spoke one language. As cultures moved, they brought this language. But, depending on the locale where they moved, certain words fell into disuse as being superfluous, extraneous, or simply not applicable anymore. Meanwhile, other countries retained these words but dropped other, und so weiter. The Torah, being written in the original lashon, would have made use of all these words. So, while we attribute them to the Greeks or Arameans, because they use them now, or most recently, we must look back at when Torah was written down. These are not loan words from future civilizations, but rather future civilizations so happened to be the sole inheritors of these otherwise lost words. To me, then, Hebrew originally had 23 proto-Sinaitic letters, one was concealed, but with the migration of different semitic groups letters which were once bunched together became expanded to the full 29 lettered Old Southern Arabian found primarily in Yemen which has been culturally isolated for most of their existence.] My Rabbi, R' Hecht, was discussing Zephanya 3:9 which says in the Future the world will speak with a pure tounge and he pointed out that it doesn't mean one language. See the Targum Yonatan on Devarim 27:5 (that the Torah will be read in one language but interpreted in 70). We see this now with nuggunim and zemirot sung in Russia, Yiddish, English, polish, etc., but each song has its local particularités and flavor and yet singularly relate to the one true G-D. That fits perfectly well with the overall context we find the number 70 in. Rabbi Dr. Hillel ben David cites extensive sources (mostly kosher) showing that the number seventy signifies a primary way of establishing an elevated connection, of building a community.
While 20 connotes spiritual blindness, 30 is connected with gestation, 40 birth, 50 transcendence, 60 is the number of transformation, but 70 is always associated with redemption (we just have to open our eyes).
Mahara”l writes that the number seventy is critical in the turning points of history: After the Flood, seventy nations descended from Noach; seventy languages emerged at the building of the Tower of Babel; the Jewish nation began with the seventy people who came with Jacob to Egypt; and in the World to Come, the seventy prime nations will recognize HaShem as the One and Only Ruler of the world.