Should you talk during sex or just make grunting and moaning noises?
Why not, (d) ALL OF THE ABOVE? The best answer to your reasonable question would most certainly include talking with your partner about whether it would be okay to chat a bit while sexually engaged.
Grunting and moaning, and even silence, by themselves aren't bad, but like cave dwellers from yesteryear, these sounds can limit your expressing what's really on your mind, and may foster misunderstanding and miscommunication about what you do and don't want. This raises another question: do you have an idea of what you'd like to say to your partner during sex? Sex talkers' "conversations" range from a slow, seductive shower of compliments such as, "Your eyes look so beautiful... you're so hot... you feel so good... you're so hairy;" to the fantasy-filled, "Being stranded on this deserted island with you means we can stay here forever;" to the more direct, "I want you" or "I love you." You can also gather information about what rocks your companion's boulders, and how s/he should pet your dinosaur — in the name of more enjoyable, consensual, and safer sex.
And, for those who long for lengthier sex-play, discussing amongst yourselves while doing it can be a nice remedy for the "Oh, baby... yeah... I'm... Goodnight" syndrome.
One of the great things about intimacy between people is that, with trust and respect established, you can feel safe and sure to know that whatever is said stays with both of you, bringing you closer.Alice!