fred responds to certain vocal inflections, particularly high-pitched ones. He also reacts predictably (ashamedly) to a certain 'angry' tone.
fred also responds predictably to certain strings of phonemes. Prominent examples are 'cookie', and 'fred'. Fortunately, fred is illiterate, so 'c-o-o-k-i-e' does not induce the same reaction.
fred and i often achieve coordination of action. If i want him to bring back a tennis ball, i simply wave it in front of him, and then throw it while saying 'fetch!'. Fred retrieves the ball, and then i say 'drop it!', and he deposits it at my feet so that the process can be repeated.
fred also seems to have a limited capacity for operating under the principles of reference. upon hearing 'where's cristi?' he usually runs to the window, and, if he sees my car, runs to the back door. 'out?' spoken with a dramatically rising tone usually causes him to run to the back door as well. additionally, the afforementioned 'cookie' example demonstrates that it is possible (to a limited extent) to communicate with fred about things and people that are not present.
I would also like to point out that certain conventions are in place such that i might be able to approach a dog i had never met before (let us say an american dog), and achieve coordination with it by asking it to 'sit', 'stay', 'shake hands', etc.
and if that's not language, i don't know what is.