YOSEF KNEW THE 70 LANGUAGES
בראשית מא, מד וַיֹּאמֶר פַּרְעֹה אֶל-יוֹסֵף אֲנִי פַרְעֹה וּבִלְעָדֶיךָ לֹא-יָרִים אִישׁ אֶת-יָדוֹ וְאֶת-רַגְלוֹ בְּכָל-אֶרֶץ מִצְרָיִם
סוטה דף לו/ב א"ר חייא בר אבא אמר רבי יוחנן בשעה שאמר לו פרעה ליוסף ובלעדיך לא ירים איש את ידו וגו' אמרו איצטגניני פרעה עבד שלקחו רבו בעשרים כסף תמשילהו עלינו אמר להן גנוני מלכות אני רואה בו אמרו לו א"כ יהא יודע בשבעים לשון בא גבריאל ולימדו שבעים לשון לא הוה קגמר הוסיף לו אות אחת משמו של הקב"ה ולמד שנאמר (תהילים פ"א) עדות ביהוסף שמו בצאתו על ארץ מצרים שפת לא ידעתי אשמע
Clearly, the Gemara explains the end of the verse in Tehillim that ‐I did not know, I understand.‐ And also note that the verse in Tehillim begins and ends with an ע (numerical value of 70).
YOSEF RECOGNIZED THE BROTHERS, BUT THEY DID NOT RECOGNIZE HIM
בראשית מב, ח וַיַּכֵּר יוֹסֵף אֶת-אֶחָיו וְהֵם לֹא הִכִּרֻהוּ
יבמות דף פח/א אמר רב חסדא מלמד שיצא בלא חתימת זקן ובא בחתימת זקן
Since the older brothers already had beards when Yosef last saw them, he was able to recognize them. However, when they last saw Yosef, he did not have a beard (too young) and now they did not recognize him. Ramban asks what about the younger brothers, Yissachar and Zevulun who were practically the same age as Yosef, how did Yosef recognize them? First, since Yosef recognized the older brothers and they came to him as a group, he was able to recognize all of them. Further, Yosef had the city guardians providing him with descriptions of all entering the city, and thus, he had more time to adjust to recognize the brothers.
REUVEN OFFERS HIS TWO SONS
בראשית מב, לז וַיֹּאמֶר רְאוּבֵן אֶל-אָבִיו לֵאמֹר אֶת-שְׁנֵי בָנַי תָּמִית אִם-לֹא אֲבִיאֶנּוּ אֵלֶיךָ
We need to understand Reuven’s offer of his two sons to die if he does not fulfill his mission.
We know (Bava Basra 118b) that Yehoshua and Calev were called ‐alive‐ since they took the portions of Eretz Yisrael from the spies, who were considered dead. Also, the one that becomes rich at the expense of another is called be enlivened by the other.
It is known that Yaacov set up for his children to inherit Eretz Yisrael (the 12 shvatim) to be explained in more detail in Parshas VeYechi.
Thus, Reuven offered that if he failed in his mission to return Binyomin safely, he would forfeit the merit of his two sons in the division of Eretz Yisrael. Therefore, this is what Reuven meant by offering his sons to be ‐dead‐, meaning without land. Similarly, the ones that did receive a portion in Eretz Yisrael were called alive. (After many years Rabbi Epstein was in Pressburg, and was told that the Chasam Sofer wrote this same explanation)