TensorFlow has APIs available in several languages both for constructing and executing a TensorFlow graph. The Python API is at present the most complete and the easiest to use, but the C++ API may offer some performance advantages in graph execution, and supports deployment to small devices such as Android.
Over time, we hope that the TensorFlow community will develop front ends for languages like Go, Java, JavaScript, Lua, R, and perhaps others. With SWIG, it's relatively easy to develop a TensorFlow interface for your favorite language.
Note: Many practical aspects of usage are covered in the TUTORIALS and HOW TO tab, and some additional documentation not specific to any particular language API is available in the RESOURCES tab.