This is the 546th most frequent Ukrainian word.
двома
"Двома" means "with two" or "by two" in English.
Here, 'двома' describes the means (two doors) through which the action is performed, and it is in instrumental plural form.
Вони вийшли з будинку разом двома дверима.
They exited the house using two doors together.
In this case, 'двома' refers to the means of communication (two languages), again utilizing the instrumental plural form.
Ми спілкувались двома мовами.
We communicated in two languages.
The word 'двома' is used as an instrumental plural form of the number 'two', indicating the instruments used for the action.