After you transcend the physical realm, verbal communication becomes redundant. People communicate through thoughts, and once Vaikuntha is reached, the only language known to them is "prema".
Basically they say that once in Vaikuntha, the soul acquires bodies of Vishnu and are with their consorts, in eternal bhakti towards the "real" Vishnu. Here "real" is within quotes because unlike Advaita, Dvaita says that jivatma and Paramatma are never same.
In the Madhya-lila section of the Chaitanya-caritamrita (21.55-57), the spiritual planets are described as larger than we can imagine, larger than any material universe. Each planet is also made of spiritual bliss. All of the inhabitants are associates of the Supreme Lord. And, in Chapter 20 (257-258), the spiritual world is referred to as the abode of the pastimes of the eternal spiritual energy.
“In those Vaikuntha planets there are many forests which are very
auspicious. In those forests the trees are wish-fulfilling trees, and
in all seasons they are filled with flowers and fruits because
everything in the Vaikuntha planets is spiritual and personal.
“In the Vaikuntha planets the inhabitants fly in their airplanes,
accompanied by their wives and consorts, and eternally sing of the
character and activities of the Lord, which are always devoid of all
inauspicious qualities. While singing the glories of the Lord, they
deride even the presence of the blossoming madhavi flowers, which are
fragrant and laden with honey.
“When the king of bees hums in a high pitch, singing the glories of
the Lord, there is a temporary lull in the noise of the pigeon, the
cuckoo, the crane, the cakravaka, the swan, the parrot, the partridge,
and the peacock. Such transcendental birds stop their own singing
simply to hear the glories of the Lord.
“Although flowering plants like the mandara, kunda, kurabaka, utpala,
campaka, arna, punnaga, nagakeshara, bakula, lily, and parijata are
full of transcendental fragrance, they are still conscious of the
austerities performed by Tulasi, for Tulasi is given special
preference by the Lord, who garlands Himself with Tulasi leaves.
“The inhabitants of Vaikuntha travel in their airplanes made of lapis
lazuli, emerald, and gold. Although crowded by their consorts, who
have large hips and beautiful smiling faces, the male inhabitants
cannot be stimulated to passion by their mirth and beautiful charms.
“The ladies in the Vaikuntha planets are as beautiful as the goddess
of fortune herself. Such transcendentally beautiful ladies, their
hands playing with lotuses and their leg bangles tinkling, are
sometimes seen sweeping the marble walls, which are bedecked at
intervals with golden borders, in order to receive the grace of the
Supreme Personality of Godhead.
“The goddesses of fortune worship the Lord in their own gardens by
offering Tulasi leaves on the coral-paved banks of transcendental
reservoirs of water. While offering worship to the Lord, they can see
on the water the reflection of their beautiful faces with raised
noses, and it appears that they have become more beautiful because of
the Lord’s kissing their faces.
“It is very much regrettable that unfortunate people do not discuss
the description of the Vaikuntha planets.”
In this way we can understand that the spiritual realm is not some form of nothingness, as some people may imagine. It is further described that there are millions of Vaikuntha planets, each with a form or expansion of the Supreme Being who resides on it. Each resident of the spiritual world goes to whichever planet has the form of God to which he or she is most attracted. Each Vaikuntha planet is self-effulgent, and many millions of times brighter than the sun. Material time and the modes of nature have no influence in the spiritual realm. There is no birth, death, old age, or disease, and no past, present, or future. Time is conspicuous by its absence. Everything, including the homes, trees, animals, and plants, are all eternal. It is full of beauty and bliss.
So to answer your question, once you reach Vaiktuntha, you and your friend will lose the identity of you and your friend, which was there only in the material realm. This is because you'll lose all your ego, and become one with the Supreme Lord. You'll also form a sense of Oneness with every other jivatma around you, knowing yourself as nothing but a spark of the Lord's energy, which ultimately converges into the Lord Himself, knowing your true identity as the Absolute Consciousness - Brahman, who is formless, yet are all forms contained in it.
P.S. For those of you confused with my mixing of philosophies, please note that I categorize myself to be an Advaitin Vaishnava.