I can see where your confusion is in this subject and I hope that I explain this correctly for you. SOA is the architecture that you application is developed on. Whether it be a windows form application, Web app or even a WPF application, you can use SOA to develop your application around. There for it is considered platform independent. So yes you can consume that service in other implementations languages. WPF does have to be developed in .NET languages but you can consume a service of another language.
I hope that helps.