Spoken-word production in Korean: A non-word masked priming and phonological Stroop task investigation

Phonological encoding in Tongan: An experimental investigation

This study is the first to report chronometric evidence on Tongan language production. It has been speculated that the mora plays an important role during Tongan phonological encoding. A mora follows the (C)V form, so /a/ and /ka/ (but not /k/) denote a mora in Tongan. Using a picture-word naming paradigm, Tongan native speakers named pictures containing superimposed non-word distractors. This task has been used before in Japanese, Korean, and Vietnamese to investigate the initially selected unit during phonological encoding (IPU). Compared with control distractors, both onset and mora overlapping distractors resulted in faster naming latencies. Several alternative explanations for the pattern of results-proficiency in English, knowledge of Latin script, and downstream effects-are discussed. However, we conclude that Tongan phonological encoding likely natively uses the phoneme, and not the mora, as the IPU.

Phonological Preparation in Korean: Phoneme, or Syllable or Another Unit?

With three experiments, the present study investigated the primary phonological preparation (PP) unit in spoken word production in Korean. Adopting the form preparation paradigm, 23 native Korean speakers named pictures in homogenous or heterogenous lists. In homogenous lists, the names of the pictures shared the same initial phoneme (Experiment 1), initial consonant + vowel (i.e., CV) body (Experiment 2), or initial consonant + vowel + consonant (CVC) syllable (Experiment 3); and in heterogenous lists, the names did not share any phonological components systematically. Compared to naming pictures in heterogenous lists, participants' naming speed was significantly faster when the initial body or the initial syllable of target names was shared. However, this form preparation effect was not shown in Experiment 1, when only the initial phoneme was shared. These results suggested that the body serves as the primary PP unit in Korean, that is, native Korean speakers tend to plan spoken words in a body-coda fashion, probably due to a joint contribution from the strong prevalence of the CV structure and early literacy instructional approach.

Orthographic properties of distractors do influence phonological Stroop effects: Evidence from Japanese Romaji distractors

In attempting to understand mental processes, it is important to use a task that appropriately reflects the underlying processes being investigated. Recently, Verdonschot and Kinoshita (Memory & Cognition, 46, 410-425, 2018) proposed that a variant of the Stroop task-the "phonological Stroop task"-might be a suitable tool for investigating speech production. The major advantage of this task is that the task is apparently not affected by the orthographic properties of the stimuli, unlike other, commonly used, tasks (e.g., associative-cuing and word-reading tasks). The viability of this proposal was examined in the present experiments by manipulating the script types of Japanese distractors. For Romaji distractors (e.g., "kushi"), color-naming responses were faster when the initial phoneme was shared between the color name and the distractor than when the initial phonemes were different, thereby showing a phoneme-based phonological Stroop effect (Experiment 1). In contrast, no such effect was observed when the same distractors were presented in Katakana (e.g., "くし"), replicating Verdonschot and Kinoshita's original results (Experiment 2). A phoneme-based effect was again found when the Katakana distractors used in Verdonschot and Kinoshita's original study were transcribed and presented in Romaji (Experiment 3). Because the observation of a phonemic effect directly depended on the orthographic properties of the distractor stimuli, we conclude that the phonological Stroop task is also susceptible to orthographic influences.

The proximate unit in Korean speech production: Phoneme or syllable?

We investigated the "proximate unit" in Korean, that is, the initial phonological unit selected in speech production by Korean speakers. Previous studies have shown mixed evidence indicating either a phoneme-sized or a syllable-sized unit. We conducted two experiments in which participants named pictures while ignoring superimposed non-words. In English, for this task, when the picture (e.g., dog) and distractor phonology (e.g., dark) initially overlap, typically the picture target is named faster. We used a range of conditions (in Korean) varying from onset overlap to syllabic overlap, and the results indicated an important role for the syllable, but not the phoneme. We suggest that the basic unit used in phonological encoding in Korean is different from Germanic languages such as English and Dutch and also from Japanese and possibly also Chinese. Models dealing with the architecture of language production can use these results when providing a framework suitable for all languages in the world, including Korean.

The Initial Functional Unit When Naming Words and Pseudowords in Thai: Evidence from Masked Priming

Cross-linguistic research indicates that the initial unit used to build an ortho-phonological representation can vary between languages and is related to the particular characteristics of the language. Thai is particularly interesting as it has both syllabic and phonemic characteristics. Using the masked priming paradigm, we examined the functional unit that is initially activated when naming monosyllabic Thai words (Experiment 1) and pseudowords (Experiment 2). In Experiment 1, the response times to the onset prime and identity (onset + vowel) conditions were not significantly different but were both significantly faster than the control prime (onset different). In Experiment 2, pseudowords were used so that the effects of orthographic vowel position could be examined. In Thai, vowels can precede the consonant in writing but phonologically follow it in speech (e.g., the written word 'odg' would be spoken as /dog/) whereas other vowels are spoken in the order that they are written. Similar results were found as in Experiment 1, as the identity prime did not have a greater facilitatory effect than the onset consonant prime. Notably, there were no orthographic effects due to orthographic vowel position. These results support the view that the onset is the initial functional unit that is activated when naming Thai visual words/pseudowords using the masked priming paradigm.