I was at a behavioural workshop last weekend where the trainer said something interesting.
Think about how you would feel with a large/big man approaching you on a narrow pathway. He looks relaxed, is walking at a steady pace and doesn't change his pace as he approaches. In this scenario most people would notice the man, make a mental note he's there and carry on walk as they were before he appeared.
Now imagine the man deliberately slows his pace and stares right at you - what would you think then? You'd probably feel menaced/threatened and want to get out of there asap or start getting ready to defend yourself.
This is what happens when either we, our dogs or us with our dogs approach another dog, especially if the other dog is already nervous or aggressive.
If on our approach we are calm, confident and keep on walking forwards without slowing or staring at the dog, we will look far less of a threat than if we deliberately slow our pace and stare directly at the dog or even stop, in which case we instantly appear more threatening.
The point of the exercise was to understand what happens when you slow down and gather up your dog's lead as you approach another dog ie, you instantly appear more threatening to the dog you're approaching and are more likely to cause a negative interaction to take place - but the principle is the same, even if you are walking without your dogs.
I would say the best thing to do is to carry on walking confidently in the direction you are going and ignore the dogs completely. If you do speak, you have to be really sure that you're not going to convey either aggression or anxiety/nerves through your voice and it's therefore better to ignore completely, whilst keeping a sneaky eye on what they're up to out of the corner of your eye.