Katy Carlson

The Effects of Parallelism and Prosody in the Processing of Gapping Structures

Two studies explored the processing of ambiguous sentences like Bill took chips to the party and Susan to the game, which may be assigned a gapping (Susan took chips) or a nongapping structure (Bill took Susan). The central question was what factors affect the ultimate interpretive preferences for these sentences. In a written questionnaire, sentences with greater parallelism between arguments in the positions of Bill and Susan received more gapping responses, though an overall bias toward the non gapping structure was seen. An auditory comprehension study showed that prosodic parallels between arguments also affected interpretation. In both experiments parallelism played a significant role in determiningan interpretation, but the simpler structure, the nongapping structure, was preferred overall.

Don't break, or do: prosodic boundary preferences

Abstract Four naturalness judgment experiments were conducted to test different hypotheses about prosodic phrasing. The hypothesis that syntactic constituents should not be broken into distinct prosodic phrases [as in Truckenbrodts Wrap constraint (Truckenbrodt, H., 1995. Phonological Phrases: Their Relation to Syntax, Focus, and Prominence. Unpublished PhD Dissertation, MIT)] was less predictive of the results of Experiments 1 and 2 than the hypothesis that constituents may be freely divided into prosodic phrases, as long as the resulting phrases are semantically coherent [Selkirk, E., 1984. Phonology and Syntax: The Relation Between Sound and Structure. MIT Press, Cambridge, MA]. The results of two further experiments confirmed Watson and Gibsons (Watson, D. G., Gibson, E., 2001. Linguistic structure and intonational phrasing. Paper presented at the Fourteenth Annual CUNY Conference on Human Sentence Processing, Philadelphia, 15–17 March 2001) claim that prosodic breaks are natural before long upcoming constituents, but did not support their hypothesis that the distance between a new item and its integration site is what motivates the presence of a prosodic phrase boundary. The results are interpreted as further evidence that the use of high level breaks in language comprehension is not governed by an invariant local mapping from syntax or processing considerations to prosody/intonation, but is related to the overall pattern of intonational choices made.

Focus and the Interpretation of Pitch Accent: Disambiguating Embedded Questions.

It has been suggested that prosodic disambiguation of sentences is largely a matter of prosodic phrasing. Ambiguities can be resolved if a prosodic break aligns with a major syntactic boundary of one structure but not another. The placement of pitch accents is viewed as playing only a supporting role (cf. Price, Ostendorf, Shattuck-Huffnagel, & Fong, 1991). This view of prosodic disambiguation does not apply tho all structures of a language. We report five experiments studying ambiguous sentences like (i) and (ii): (i) I asked the pretty little girl WHO is cold. I asked the pretty little girl who is COLD. (ii) Joshua began to wonder WHEN his girlfriend got a tattoo. Joshua began to wonder when his girl friend got a TATTOO. The presence of a prominent pitch accent on the interrogative constituent (who, when) biased listeners to a emmbedded question interpretation whereas its absence biased thhem to a relative clause(i) or temporal adjunct(ii) analysis. The results suggest that accent, like prosodic breaks, can play a central role in guiding sentence comprehension.

Tracking the what and why of speakers' choices: prosodic boundaries and the length of constituents.

The rational speaker hypothesis (Clifton, Carlson, & Frazier, 2002) claims that speakers are selfconsistent, employing intonation in a manner consistent with their intended message. Preceding a constituent by a prosodic boundary that is not required by the grammar often signals that this constituent is not part of the immediately preceding phrase. However, speakers tend to place prosodic boundaries before and after long constituents. The question is whether prosodic boundaries will have a larger influence on listeners’ choice of an analysis when they flank short constituents than when they flank long ones. The results of two listening experiments indicate that they do, suggesting that listeners attend not just to properties of the input signal, but also to the reasons why speakers produce those properties.

Reassignment of consonant allophones in rapid dialect acquisition

Abstract In an experiment spanning a week, American English speakers imitated a Glaswegian (Scottish) English speaker. The target sounds were allophones of /t/ and /r/, as the Glaswegian speaker aspirated word-medial /t/ but pronounced /r/ as a flap initially and medially. This experiment therefore explored (a) whether speakers could learn to reassign a sound they already produce (flap) to a different phoneme, and (b) whether they could learn to reliably produce aspirated /t/ in an unusual phonological context. Speakers appeared to learn systematically, as they could generalize to words which they had never heard the Glaswegian speaker pronounce. The pattern for /t/ was adopted and generalized with high overall reliability (96%). For flap, there was a mix of categorical learning, with the allophone simply switching to a different use, and parametric approximations of the “new” sound. The positional context was clearly important, as flaps were produced less successfully when word-initial. And although there was variability in success rates, all speakers learned to produce a flap for /r/ at least some of the time and retained this learning over a weeks time. These effects are most easily explained in a hybrid of neo-generative and exemplar models of speech perception and production.

Form and function: Optional complementizers reduce causal inferences

Many factors are known to influence the inference of the discourse coherence relationship between two sentences. Here, we examine the relationship between two conjoined embedded clauses in sentences like The professor noted that the student teacher did not look confident and (that) the students were poorly behaved. In two studies, we find that the presence of that before the second embedded clause in such sentences reduces the possibility of a forward causal relationship between the clauses, i.e., the inference that the student teacher’s confidence was what affected student behavior. Three further studies tested the possibility of a backward causal relationship between clauses in the same structure, and found that the complementizer’s presence aids that relationship, especially in a forced-choice paradigm. The empirical finding that a complementizer, a linguistic element associated primarily with structure rather than event-level semantics, can affect discourse coherence is novel and illustrates an interdependence between syntactic parsing and discourse parsing.

Focus and VP Ellipsis

In spoken English, pitch accents can convey the focus associated with new or contrasted constituents. Two listening experiments were conducted to determine whether accenting a subject makes its predicate a more tempting antecedent for an elided verb phrase, presumably because the accent helps focus the subject of the antecedent clause, increasing its likelihood of contrasting with the subject of the elided clause. The results of Experiment 1 supported the predictions of this “Contrasted Remnant hypothesis” but in principle could also be caused by listeners avoiding antecedents containing a focused (F-marked) constituent. Experiment 2 disconfirmed the hypothesis that listeners avoid antecedents containing a focused constituent, although pitch accents within a potential antecedent VP affected ellipsis resolution.

The Role of Only in Contrasts In and Out of Context

Three self-paced reading experiments explored the processing of only and its interaction with context. In isolated sentences, the focus particle only predicts an upcoming contrast. Ambiguous replacive sentences (e.g., “The curator embarrassed the gallery owner in public, not the artist”) with only on the subject or object showed faster reading of the contrast phrase (“not the artist”) than without it. The position of only also influenced the phrases meaning; despite a bias toward object contrasts, subject only increased subject interpretations. If preceding context provides another reason for the focus particle, it no longer predicts an upcoming contrast. In biasing contexts including indirect questions, there was no facilitation when only marked the argument that answered the question, whereas only on the other argument slowed processing. Both only and context influenced interpretation. The results show that focus particles and questions can each influence processing of an upcoming contrast on- and off-line.

Nonlocal effects of prosodic boundaries.

Placing a prosodic boundary before a phrase may influence its syntactic analysis. However, the boundary’s effect depends on the presence, size, and position of other, earlier, prosodic boundaries. In three experiments, we extend previous results about the effect of the position of the early boundary. In sentences in which a final phrase may modify either a local verb or an earlier verb, a boundary immediately after the first verb leads to more first-verb attachments than when the earlier boundary appears in another position between the two verbs (Experiments 1 and 2). This effect cannot be attributed to weaker effects of more distant boundaries (Experiment 2), but is likely due to the first verb being more prominent when a boundary immediately follows it, since similar effects are observed when the verb is accented (Experiment 3). The results support the informative boundary hypothesis and show that the impact of earlier, nonlocal boundaries is not fully uniform.

Syntactic Structure Guides Prosody in Temporarily Ambiguous Sentences

A pair of speaking and listening studies investigated the prosody of sentences with temporary Object/Clause and Late/Early Closure ambiguities. Speakers reliably produced prosodic cues that allowed listeners to disambiguate Late/Early Closure sentences, but only infrequently produced prosody that disambiguated Object/Clause sentences, as shown by the results of listening studies. The two continuations for Object/Clause sentences were not pronounced with identical prosody, but the differences in their productions were not helpful to listeners. Speakers’ different performance on the two sentence types is traced to their different syntactic structures. These results illustrate the importance of the syntax—prosody mapping in production and test the prosodic predictions of syntax—prosody models like that of Watson and Gibson (2004).