If my wife and I invite 2 adult males to our Shabbat table, who do not know how to bench (and/or possibly even read Hebrew), what is the halacha considering the m’zumen?

One should make a Mezuman with them even though they do not speak Hebrew in order that they may come closer to keeping the mitzvot. Though, one should explain the meaning of the words and of the mezuman itself beforehand. Rabbi Ro'i Margalit