Service-oriented architecture (SOA) is increasingly popular for constructing eLearning systems. SOA encourages the separation of process from underlying services. The separation is also advocated by IMS Learning Design, an international standard for describing a learning process. Despite the apparent congruence and the recent proposals of several SOAs for eLearning, existing eLearning systems have yet to take full advantage of the process-service separation and are denied of a number of quality attributes promised. In this paper, we describe a new approach, which incorporates process translation and a three-layer SOA, for delivering specification-based eLearning processes. Specially, an eLearning course description specified in IMS Learning Design is translated into a process of Business Process Execution Language (BPEL). The translated BPEL process is then executed on a BPEL engine, which powers the process service layer of the SOA and keeps the learning processes separated from the underlying Web services. The architecture achieves extensibility, reusability, and ease of integration by allowing advanced eLearning standards to be incrementally implemented as a group of collaborating processes in BPEL. Translation rules from IMS Learning Design into BPEL are presented. The benefits of the proposed approach are investigated and compared with existing eLearning architectures.