וַיֹּ֣אמֶר יְהוָ֗ה הֵ֣ן עַ֤ם אֶחָד֙ וְשָׂפָ֤ה אַחַת֙ לְכֻלָּ֔ם וְזֶ֖ה הַחִלָּ֣ם לַעֲשׂ֑וֹת וְעַתָּה֙ לֹֽא־יִבָּצֵ֣ר מֵהֶ֔ם כֹּ֛ל אֲשֶׁ֥ר יָזְמ֖וּ לַֽעֲשֽׂוֹת׃
et il dit: "Voici un peuple uni, tous ayant une même langue. C’est ainsi qu’ils ont pu commencer leur entreprise et dès lors tout ce qu’ils ont projeté leur réussirait également.
Rashi on Genesis
הן עם אחד BEHOLD, THEY ARE ONE PEOPLE — They possess all the advantage of being one people and of having one language common to all of them, and this is what they begin to do!
Sforno on Genesis
הן עם אחד, the only way I can stop them from carrying out their unanimously approved plan is to sow the seeds of discord between them. The instrument of bringing this about is to confuse their language. Basically, people’s disagreements are either religious, (philosophical) in nature, or they result from misunderstanding what they mean when they speak. These people had been of one mind in matters of religion, seeing that they had all agreed with the mistaken idolatrous philosophy shared by mankind at that time. In spite of such apparently good reasons for disagreeing with one another, they did not misunderstand each other.