As much as many people hate to hear it, you may need to invest in a bark collar. Dogs like to bark, it is often how they establish their relationship with other dogs and it is how they alert their owners of a "weird" or "dangerous" situation, like encountering an unfamiliar dog. A good bark collar (look for reviews when buying, probably not going to be the cheapest one on the market) will reduce and even eliminate your dog's barking quickly and effectively. It worked on my Pit Mix in 2 days! She no longer even has to wear it.