number feature

Singular-plural asymmetry in L2 English number processing: A sentence-picture matching study of Japanese learners of English

/ Yu Tamura

Aims and Objectives

This study investigates whether Japanese learners of English automatically map English number morphology onto conceptual number in both directions. Two research questions guide the study:
1) Mismatch costs: Do L2 learners show reaction-time slowdowns when:
a) A singular noun is paired with a plural picture?
b) A plural noun is paired with a singular picture?
L1 speakers serve as a baseline to establish expected mismatch effects.
2) Directional asymmetry: If mismatch costs occur, are they equivalent in both directions, or is there a systematic asymmetry?

Methodology

The study employed a sentence-picture matching task that crossed noun number (singular vs. plural) with picture number (match vs. mismatch), extending previous unidirectional designs to test both directions of number mapping in L2 processing. Reaction times (RTs) served as the primary dependent measure.

Data and Analysis

Thirty-two L1 English speakers and ninety-six Japanese L2 learners (CEFR B1–B2) each completed 200 trials (80 target items and 120 fillers). Incorrect trials were excluded, and extreme RTs were trimmed before the analysis. RTs were analyzed using inverse-Gaussian generalized linear mixed-effects models, with sentence length and trial order included as covariates.

Findings

L1 speakers showed significant RT slowdowns for both mismatch types, confirming automatic singular-plural mapping. In contrast, L2 learners exhibited a slowdown only when a singular noun was paired with a plural picture, and no effect when a plural noun was paired with a singular picture, revealing a processing asymmetry. For Japanese learners, plural nouns did not consistently activate conceptual plurality.

Originality

This is the first study to examine both directions of morphological-conceptual number mismatch in L2 processing, extending Jiang et al. (2017), which tested only the singular-noun/plural-picture mapping.

Significance

These findings refine the Morphological Congruency Hypothesis by showing that incongruent L2 morphemes can lead to direction-specific processing weaknesses in learners’ conceptual mapping.

Tamura, Y. (2026). Singular-plural asymmetry in L2 English number processing: A sentence-picture matching study of Japanese learners of English. International Journal of Bilingualism. https://doi.org/10.1177/13670069261422017 [Open Access]

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Is cats one word or two? L2 Learners’ processing of number marking in English from the viewpoints of form–meaning mapping.

/ Yu Tamura

This study examined number marking comprehension among Japanese learners of L2 English, whose L1 does not have an obligatory number marking system. The study conducted an online sentence comprehension experiment with 96 L1-Japanese learners and 32 native speakers of English, wherein participants engaged in a self-paced reading with Stroop-like number judgment tasks. Participants were required to determine the number of single words in stimuli (e.g., _cat_/_cats_, one word; _the cats_/_the cat_, two-word sets), and their judgment time was measured for singular and plural words. The results indicated that both groups took more time to judge single plural nouns, suggesting that Japanese L2 learners of English automatically activate plurality in online sentence comprehension as native speakers do. In contrast, neither group showed an interference effect of singularity in judging singular two-word noun sets (_the cat_), unless the singularity is explicitly marked by indefinite article (_a cat_). The lack of interference may be because of unmarkedness of singularity.

Tamura, Y. (2023). Is cats one word or two? L2 Learners’ processing of number marking in English from the viewpoints of form–meaning mapping. Second Language Research. https://doi.org/10.1177/02676583231188933

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Investigation of the relationship between animacy and L2 learners’ acquisition of the English plural morpheme

/ Yu Tamura

It has been argued that languages differ in the extent to which they allow plural forms of nouns according to the Animacy Hierarchy. Japanese distinguishes between animate and inanimate nouns; the latter are less likely to receive plural markers (e.g., ? hon‐tachi), unlike English. This L1‐L2 difference might cause difficulty in acquiring the plural morpheme. The present study thus investigates the influence of animacy on the processing of the English plural morpheme in online sentence processing. In this study, 34 Japanese university students engaged in a moving window version of a self-paced reading task, during which they also judged whether the number of words presented was one or two when prompted. If animacy matters, Japanese EFL learners might not show an interference effect of this second task for inanimate nouns. However, as no such effect was found, the prediction based on the animacy hierarchy was not confirmed.

Tamura, Y.  (2023). Investigation of the relationship between animacy and L2 learners’ acquisition of the English plural morpheme. Journal of Psycholinguistic Research, 52, 675–690. https://doi.org/10.1007/s10936-022-09915-2 [Read Online]

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Japanese EFL Learners’ Sentence Processing of Conceptual Plurality: An Analysis focusing on reciprocal verbs

/ Yu Tamura / 1件のコメント

This study aimed to investigate how Japanese EFL learners, whose first language does not have obligatory morphological number marking, process conceptual plurality. The targeted structure was reciprocal verbs, which require conceptual plurality to interpret their meanings correctly. The results of a sentence completion task (SCT) confirmed that participants could use reciprocal verbs reciprocally in English. In a self-paced reading experiment, participants read sentences with reciprocal verbs and those with optionally transitive verbs (e.g., while the king and the queen kissed/left the baby read the book in the bed). There was no reading time delay for reciprocal verbs but a delay for optionally transitive verbs. Therefore, the participants succeeded in processing L2 conceptual plurality in the online sentence comprehension task.

Tamura, Y., Fukuta, J., Nishimura, Y., Harada, Y., Hara, K., & Kato, D. (2019). Japanese EFL learners’ sentence processing of conceptual plurality: An analysis focusing on reciprocal verbs. Applied Psycholinguistics, 40, 59–91. doi:10.1017/S0142716418000450 [Author Manuscript]

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L2 word processing of singular- and plural-dominant nouns in English

/ Yu Tamura

This study explored the word frequency effects of plural and singular nouns in second language (L2) word processing. Although previous studies have pointed out the influence of word frequency in accessing L2 words and their corresponding concepts or the first language (L1) translations (e.g., Habuchi, 2005), they have not taken up the frequency dominance in singular and plural forms as done by Baayen, Dijkstra, and Schreuder (1997). Thus, the present study conducted two types of matching task to investigate the associations linking the L2 word, L1 translation, and the concepts of singular-dominant words (e.g., cat, photo; k = 12) and plural-dominant words (e.g., sock, bean; k = 12) on the basis of the revised hierarchical model (RHM) (Kroll & Stewart, 1994). Thirty-two Japanese learners of English participated in the study. In the experiment, the target L2 words were presented, either in singular or plural forms, on a computer screen followed by either their L1 translation (L1 matching) or a representative picture (picture-matching), and the participants were asked to judge whether the L2 word matched the L1 translation or picture. Reaction times for each trial were recorded and analyzed. The results revealed a significant interaction between the frequency dominance and word form, indicating that singular-dominant words and plural-dominant words were processed differently.

Tamura, Y. & Nishimura, Y. (2016). L2 word processing of singular- and plural-dominant nouns in English. Journal of the Japan Society for Speech Sciences, 17, 17-37.