In looking at differential difficulties at the different linguistic modules and interfaces, this paper argues for the Bottleneck Hypothesis (Slabakova 2008). It is argued that narrow syntactic knowledge comes before accurate knowledge of morphology in production and comprehension of a second language. Functional morphology is uniformly hard: it is harder for low-educated native speakers than for non-native speakers. In processing complex syntax, low-educated native speakers who have had little exposure to complex constructions may be at a disadvantage compared to non-native speakers. It is also argued that once the inflectional morphology is learned, learners are aware of all its semantic consequences, taught and untaught. Even at the syntax-discourse interface, acquisition of properties unavailable from the L1 is possible. At the semantics-pragmatics interface, L2 learners transfer universal properties like Gricean maxims. The rationale of the Bottleneck Hypothesis is as follows: (1) inflectional morphology reflects syntactic and semantic differences between languages; (2) narrow syntactic operations and meaning calculation are universal; (3) in order to acquire syntax and meaning in a second language, the learner has to go through the inflectional morphology; (4) hence, morphology is the bottleneck of acquisition
