From Keil and Delitzsch's Commentary:(From here)
By the firm establishment of an ungodly unity, the wickedness and
audacity of men would have led to fearful enterprises. But God
determined, by confusing their language, to prevent the heightening of
sin through ungodly association, and to frustrate their design. "Up"
(הבה "go to," an ironical imitation of the same expression in Genesis
11:3 and Genesis 11:4), "We will go down, and there confound their
language (on the plural, see Genesis 1:26; נבלה for נבלּה, Kal from
בּלל, like יזמו in Genesis 1:6), that they may not understand one
another's speech."
They further state:
When it is stated, first of all, that God resolved to destroy the
unity of lips and words by a confusion of the lips, and then that He
scattered the men abroad, this act of divine judgment cannot be
understood in any other way, than that God deprived them of the
ability to comprehend one another, and thus effected their dispersion.
The argument of the Personages of God is given a careful rendering in their Gen. 1:26 commentary: 3 arguments for the "Us" are given,
1) Pluralis Majestatis-the understanding that God is Trinitarian; this is the Early Church Father's understanding, which God reveals Himself through time as 3 Persons
2) An address by God Himself-the subject and object being identical
3) An address to spirits and angels who are present and stand in His council
The last argument founders,
upon this rock: either it assumes without sufficient scriptural
authority, and in fact in opposition to such distinct passages as
Genesis 2:7, Genesis 2:22; Isaiah 40:13 seq., Genesis 44:24, that the
spirits took part in the creation of man; or it reduces the plural to
an empty phrase, inasmuch as God is made to summon the angels to
cooperate in the creation of man, and then, instead of employing them,
is represented as carrying out the work alone. Moreover, this view is
irreconcilable with the words "in our image, after our likeness;"
since man was created in the image of God alone (Genesis 1:27; Genesis
5:1), and not in the image of either the angels, or God and the
angels.(From here)
Furthermore,
just as little ground is there for regarding the plural here and in
other passages (Genesis 3:22; Genesis 11:7; Isaiah 6:8; Isaiah 41:22)
as reflective, an appeal to self; since the singular is employed in
such cases as these, even where God Himself is preparing for any
particular work (cf. Genesis 2:18; Psalm 12:5; Isaiah 33:10)
The only conclusion is
No other explanation is left, therefore, than to regard it as pluralis
majestatis, - an interpretation which comprehends in its deepest and
most intensive form (God speaking of Himself and with Himself in the
plural number, not reverentiae causa, but with reference to the
fullness of the divine powers and essences which He possesses) the
truth that lies at the foundation of the trinitarian view, viz., that
the potencies concentrated in the absolute Divine Being are something
more than powers and attributes of God; that they are hypostases,
which in the further course of the revelation of God in His kingdom
appeared with more and more distinctness as persons of the Divine
Being.
Therefore "Us" in Gen. 11:7 must be correctly identified as God, being in 3 Persons, who in time will manifest these Personages to all creation.