Rashi on Genesis 11:6/רש"י על בראשית י״א:ו׳

1הן 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!

2החלם is infinitive, like אמרם “their speaking”. עשותם “their doing” (i.e. “they speak”, “they do”) — so here: “they begin to do”) (Genesis Rabbah 38:9).

3לא יבצר מהם וגו' לעשות This is a question (although the ה which introduces an interrogative sentence is absent): SHALL THEY NOT BE RESTRAINED FROM DOING WHAT THEY IMAGINE TO DO? The word יבצר means “restraining”, as the Targum understands it; a similar instance is, (Psalms 76:13) “He restrains (יבצור) the spirit of princes”.