1) If we look carefully at the Gemara, we notice that it does not say that the Torah was given in all languages. What the Gemara says is that the Torah is said in all languages. There is a dispute between Rashi and Tosfos what this means. Rashi writes that it means that one may read the Torah in public in any language. Tosfos writes that it means that whenever there is a Mitzvah to read a passage of the Torah (for example, the Mitzvah of Chalitzah, in Devarim 25:8, when the sister-in-law says that her brother-in-law does not want to do Yibum in order to perpetuate the name of the deceased husband), this passage may be said in any language.

2) We notice that the above discussion is not about what language the Torah was given in, but about what language it can be read in. However, everyone agrees that the Torah was given in Hebrew. This is stated in the Gemara in Sotah 33a which tells us that when the verse (Devarim 27:14) says, "And the Leviyim answered... with a loud voice," this means that they answered in the Holy Tongue. We derive this from a Gezeirah Shavah. Here it says "a loud voice " and in Shemos 19:19 we learn that Elokim answered with a " voice ." Just as the voice with which Hash-m gave the Torah was Lashon ha'Kodesh, so too was the voice of the Leviyim in Lashon ha'Kodesh. Rashi (DH Ya'anenu) writes that the Torah was given in Lashon ha'Kodesh.

3) We learn from the Gemara in Sotah that the Torah was given in the Holy Tongue. This is what Rashi means at the beginning of Megilah 17b when he says that "b'Havayasan" means Lashon ha'Kodesh, because the Torah came into existence in Hebrew.

4) While we have seen above that the Torah was given in Hebrew, it should be made clear that later it was transmitted to the world in 70 languages. Rashi on Chumash mentions this in a couple of places. The first is in Devarim 1:5: "Moshe started to explain this Torah." Rashi writes that Moshe Rabeinu explained it in 70 languages. In addition, in Devarim 27, the Torah tells us how, when Bnei Yisrael crossed the Jordan River, they set up large stones at the crossing. Devarim 27:8 tells us, "And you shall write on the stones all the words of this Torah, 'well explained.'" Rashi writes that "well explained" means that Moshe explained the Torah in 70 languages.

5) We see that while the Torah was given in Hebrew, as Rashi writes in Sotah 33a, and as we saw that "b'Havayasan Yehu" teaches that the Torah came into existence in Hebrew, afterwards Moshe elucidated the Torah to the whole world so that everyone in the world should have the opportunity to know what is in the Torah.

6) It seems that it was Moshe Rabeinu who translated and transmitted the Torah into every language, as the Midrash Rabah (Bereshis 49:2) states that "Moshe meditated (Hogeh) the Torah in 70 languages."

7) I looked more into this very good question and I found the following statement in the Tzelach (by the author of the Noda b'Yehudah) on Maseches Berachos (13a, DH Sham b'Havayasan Yehu;

in Berachos there is a Sugya similar to the Sugya in Megilah):

"Nobody ever disagreed with the fact that every speech which went out of the mouth of ha'Kadosh Baruch Hu on Sinai was divided into 70 languages, as Tosfos wrote in our Sugya."

a) What I wrote in my previous answers does not conform with the words of the Tzelach, so we will have to learn the Tzelach. Before doing so, I will refer us to the Gemara in Shabbos 88b where Rebbi Yochanan and Tana d'Vei Rebbi Yishmael said that every speech which left the mouth of Hash-m was split into 70 languages. This is a source for the Tzelach.

b) The Tzelach makes a distinction between the way the Torah was said on Har Sinai and the way it was written. The Torah was written specifically in Hebrew. The Tzelach cites a source for this from Sanhedrin 21b, where everyone agrees that the Torah was given on Mount Sinai in Lashon ha'Kodesh. There is a dispute in the Gemara there concerning what sort of writing it was. Was it "Ashuris," which is the same as the writing that we use now in a Sefer Torah, or was it "Ivri," an earlier form of Hebrew script? However, everyone agrees that the written language of the Torah was Hebrew.

c) The Tzelach writes that "b'Havayasan" refers to "Havayos Kesivasan" -- how the "writing of the Torah came about." This is why the last line of Megilah 17a states that, according to Rebbi, Keri'as Shema is read how it is written, because the Torah was written only in Hebrew, so Keri'as Shema must be read also in Hebrew. Similarly, when Rashi writes (beginning of 17b) that b'Havayasan is in Lashon ha'Kodesh, this means that the Torah was written in Lashon ha'Kodesh. It is not referring to how the Torah was said on Har Sinai, or how it is read in Keri'as ha'Torah, or how it is read when the sister-in-law says the Parshah of Chalitzah, etc.

d) So, according to the Tzelach, the answer to your question, Joseph, is that when the Torah was given it was said in every language, but written only in Hebrew, and b'Havayasan and "v'Hayu" refer to the writing.

Kol Tuv,

Dovid Bloom