Left-Edge Boundary Tones and Syntactic Structure

In a third study (Roll, Horne, and Lindgren, submitted), the effects of left-edge boundary tones on the processing of embedded main clauses (e.g. ... att Gunnar kommer inte ‘... that Gunnar comes not’) and subordinate clauses introduced by att ‘that’ (e.g. ... att Gunnar inte kommer ‘... that Gunnar not comes’) were measured using Event-Related Potentials.

Without a left-edge boundary tone, embedded main clauses gave rise to a P600 effect as compared to structurally ambiguous clauses. The P600 effect was suppressed when the embedded main clauses were associated with a left-edge boundary tone. However, the tone had no effect on the processing of subordinate clauses. Thus, the presence of att ‘that’ makes a subordinate clause structurally expected. A subsequent left-edge boundary tone yields an embedded main clause almost equally expected, but does not make subordinate clauses less expected. The stable effect of word order and prosody on the P600 contrasted with a large disagreement between subjects as regards acceptability judgments, where there was no effect of prosody, showing the non-normative status of the tone. The study thus shows how a prosodic feature with a low degree of grammaticalization can activate a particular syntactic structure without inhibiting a parallel competing structure in the processing of sentences.