Many embedded DSP systems can be characterized as streaming applications. Imperative programming languages are ill suited for describing the concurrency within these DSP systems. SPEX is a language extension designed to let the programmers describe the inherent parallelism within DSP systems. In this paper, we highlight SPEX's language features for describing the streaming computation and communication patterns of DSP systems, and allowing the compiler to generate efficient code for embedded DSP architectures. This language extension is based on the parameterized dataflow computation model, with modifications to better describe DSP systems' complex streaming patterns. SPEX is applied as an extension onto the C++ programming language. It consists of a set of language constructs for describing the semantics of parameterized dataflow computations, and a set of language restrictions for helping the embedded compilation process. In this paper, the W-CDMA wireless protocol is used as our case study.