The Processing of Linguistic Prominence.

Prominence, the expression of informational weight within utterances, can be signaled by prosodic highlighting (head-prominence, as in English) or by position (as in Korean edge-prominence). Prominence confers processing advantages, even if conveyed only by discourse manipulations. Here we compared processing of prominence in English and Korean, using a task that indexes processing success, namely recognition memory. In each language, participants' memory was tested for target words heard in sentences in which they were prominent due to prosody, position, both or neither. Prominence produced recall advantage, but the relative effects differed across language. For Korean listeners the positional advantage was greater, but for English listeners prosodic and syntactic prominence had equivalent and additive effects. In a further experiment semantic and phonological foils tested depth of processing of the recall targets. Both foil types were correctly rejected, suggesting that semantic processing had not reached the level at which word form was no longer available. Together the results suggest that prominence processing is primarily driven by universal effects of information structure; but language-specific differences in frequency of experience prompt different relative advantages of prominence signal types. Processing efficiency increases in each case, however, creating more accurate and more rapidly contactable memory representations.

Prosodic cues in infant-directed speech facilitate young children's conversational turn predictions.

Experienced language users are able to predict when conversational turns approach completion, which allows them to attend to and comprehend their interlocutor's speech while planning and accurately timing their response. Adults primarily rely on lexico-syntactic cues to make such predictions, but it remains unknown what cues support these predictions in young children whose lexico-syntactic competence is still developing. This study assessed children's reliance on prosodic cues, specifically when predicting conversational turn transitions in infant-directed speech (IDS), the speech register that they encounter in day-to-day interactions that is characterized by exaggerated prosody compared with adult-directed speech (ADS). Young children (1- and 3-year-olds) completed an anticipatory looking paradigm in which their gaze patterns were recorded while they observed conversations that were produced in IDS or ADS and that contained prosodically complete utterances (lexico-syntactic and prosodic cues) and prosodically incomplete utterances (only lexico-syntactic cues). The 1-year-olds anticipated more turns that were signaled by prosodic cues (i.e., prosodically complete utterances) only in IDS, whereas the 3-year-olds did so in both IDS and ADS. These findings indicate that children anticipate the completion of conversational turns by relying on prosodic information in speech and that the prosodic exaggeration of IDS supports this ability while children's linguistic and conversational skills are still developing.

Inducing speech errors in dysarthria using tongue twisters.

Although tongue twisters have been widely use to study speech production in healthy speakers, few studies have employed this methodology for individuals with speech impairment. The present study compared tongue twister errors produced by adults with dysarthria and age-matched healthy controls. Eight speakers (four female, four male; mean age = 54.5 years) with spastic (mixed-spastic) dysarthria of varying aetiology (cerebral palsy, multiple sclerosis, multiple system atrophy) and eight controls (four female, four male; mean age = 56.9 years) were audio-recorded producing tongue twisters. One word in each tongue twister was marked for prominence. Speakers with dysarthria produced significantly more errors and spoke slower than healthy controls. The effect of prominence was significant for both groups-words spoken with prosodic prominence were significantly less error prone compared with words without prominence. While both groups produced most errors on words in the third position (of four-word utterances), speakers with dysarthria also produced high rates of errors on the first and fourth words. This preliminary investigation demonstrated the promise of applying the tongue twister paradigm to speakers with dysarthria and contributes to the evidence base for the implementation of prosodic strategies in speech intervention.

Phonological Encoding in Mandarin Chinese: Evidence from Tongue Twisters.

Models of connected speech production in Mandarin Chinese must specify how lexical tone, speech segments, and phrase-level prosody are integrated in speech production. This study used tongue twisters to test predictions of the two different models of word form encoding. Tongue twisters were constructed from 5 sets of characters that rotated pairs of initial segments or pairs of tones, or both, across format (ABAB, ABBA), and across position of the characters in four-character tongue twister strings. Fifty two native Mandarin Chinese speakers read aloud 120 tongue twisters, repeating each one six times in a row. They made a total of 3503 (2.34%) segment errors and 1372 (.92%) tone errors. Segment errors occurred on the onsets of the first and third characters in the ABBA but not ABAB segment-alternating tongue twisters, and on the onsets of the second and fourth characters of the tone-alternating tongue twisters. Tone errors were highest on the third and fourth characters in the tone-alternating tongue twisters. The pattern of tone errors is consistent with the claim that tone is associated to a metrical frame prior to segment encoding, while the format by position interaction found for the segment-alternating tongue twisters suggest articulatory gestures oscillate in segment production as proposed by gestural phonology.

The influence of speaker and listener variables on intelligibility of dysarthric speech.

UNLABELLED: This study compared changes in speech clarity as a function of speaking context. It is well documented that words produced in sentence contexts yield higher intelligibility than words in isolation for speakers with mild to moderate dysarthria. To tease apart the effect of speaker and listener variables, the current study aimed to quantify differences in word intelligibility by speaking task. Eighteen speakers with dysarthria produced a set of 25 words in isolation and within the context of a sentence. Eighteen listeners heard a randomized sample of the isolated productions, single words extracted from the sentences, and the full unaltered sentences. Listeners transcribed what they heard and rated their confidence. Words produced in isolation were just as intelligible as words produced in sentence context, both of which were more intelligible than extracted words. In other words, speakers reduced articulatory clarity in sentence production compared to isolated productions; listeners were able to cope with this reduction in clarity when they had access to contextual information but not when these cues were removed in the extracted condition. These findings are consistent with Lindblom's hypo-hyperarticulation theory in that adults with dysarthria appear to be modulating articulatory precision based on listener/task variables. This work has implications for clinical practice in that isolated word and sentence production tasks yielded equivalent intelligibility findings. LEARNING OUTCOMES: Readers will recognize that speech intelligibility is influenced by speaker and listener variables and thus the choice of speaking and listening task may yield different results. Commonly held clinical belief is that sentence production tasks yield inflated intelligibility scores but we did not find that in this sample. Findings also indicate that speakers with dysarthria may modulate articulatory clarity in response to listener needs which should be considered in treatment planning.