There is one and only one common human language processing system and a variety of linguistic data to be processed. This system must operate opportunistically with certain areas of freedom. Within that system there is competition between the first and second languages on all levels and through all stages of development. Some processing procedures are universal across languages, and some are language-specific. In addition, there is much heterogeneity and variance among individuals. What the second language learner must learn is to make use of the processing capacity gained in the first language and to sort or filter out those processes that cannot handle second language processing tasks. The number of universal processes appears to be very large. Transfer is the use of these processes across languages, and interference is the lack or inadequacy of the sorting or filtering procedure. Any future theory of language acquisition should begin with the assumption that there are many similarities between first and second language processing, and that one's first language ability has an extremely important function in second language learning. These conclusions are supported in this paper via a detailed task analysis of a three-frame, non-captioned cartoon taken from Goldman-Eisler (1961).