1. Introduction (1) nwuka ku chayk-lul sass-ni? (2) a. (3) a. (4) a. (5) a. (6) a. (7) a. 2. Topic and contrastive focus as a grammatical natural class 2.1 Semantic evidence: discourse presupposition 2.2. Syntactic evidence: Scrambling 2.3. What is something in common between topicand contrastive focus? 3. Implications (15) (16) (17) (18) References