moving leftward to a position on the left edge of the clause called [Spec,CP]. Thus, a derivation of the English question What did John buy? would proceed roughly as follows: [CP {Spec,CP position} John did buy what] wh-movement → [CP What did John buy] The Japanese equivalent of this sentence is as follows (note the lack of wh-movement): Japanese has an overt "question particle" (ka), which appears at the end of the sentence in questions. It is generally assumed that languages such as English have a "covert" (i.e. phonologically null) equivalent of this particle in the 'C' position of the clause — the position just to the right of [Spec,CP]. This particle is overtly realised in English by the movement of an auxiliary to C (in the case of the example above, by the movement of did to C). Why is it that this particle is on the left edge of the clause in English, but on the right edge in Japanese? Kayne suggests that in Japanese, the whole of the clause (apart from the question particle in C) has moved to the [Spec,CP] position. So, the structure for the Japanese example above is something like the following: [CP [John-wa nani-o kaimashita] C ka Now it is clear why Japanese does not have wh-movement — the [Spec,CP] position is already filled, so no wh-phrase can move to it. The relationship between surface word order and the possibility of wh-movement is seemingly obscure. A possible alternative to the antisymmetric explanation could be based on the difficulty of parsing languages with rightward movement. Dynamic antisymmetry Andrea Moro proposed Dynamic antisymmetry, a weak version of antisymmetry, which allows the generation of non-LCA compatible structures (points of symmetry) before the hierarchical structure is linearized at Phonetic Form (PF). The unwanted structures are then rescued by movement: deleting the phonetic content of the moved element neutralizes the linearization problem. Dynamic Antisymmetry aims at unifying a movement and phrase structure, which otherwise are independent properties. Antisymmetry and ternary branching Kayne proposed recasting the antisymmetry of natural language as a condition on "Merge", the operation which combines two elements into one. Kayne proposes that merging a head H and its complement C yields an ordered pair (rather than the standard symmetric set {H,C}). involves immediate temporal precedence (or immediate linear precedence) so that H immediately precedes (i-precedes) C. Kayne proposes furthermore that when a specifier S merges,