A production experiment was conducted in order to examine the acquisition of English intonation by native speakers of Japanese, and the results were analyzed within the framework developed by Pierrehumb../pdf/Th3b [3] and her colleagues. The results suggest that second language intonation is acquired on two different levels: learners first acquire the categorical patterns of the foreign intonation, and only later learn to produce native-like continuous intonational streams. This supports models in which the speech cognitive system is split into two sub-modules: a phonological component (characterized by categorical units) and a phonetic component (implementing the phonological units as a continuous articulatory/acoustic stream).