I agree with another answer, concentration during the game is at the limit, so everyone is silent. But sometimes there are various exceptions, for example, one player must pass the coach's instructions to another. I have many personal examples, the most frequent ones are when a non-gross violation occurs and at the moment of setting the ball, players can often enter into a skirmish, they say, "What *** are you doing / standing here" and stuff like that. But such long conversations, implying "Hello, how are you, how is the weather blah blah blah .." are extremely rare.
No. Professional footballers are completely focused on the game. And the location of the players on the field does not mean that two or more players will be so close to each other. And in those moments when the players are nearby (free kick, corner, penalty), they obviously have no time for that.