When inferring the meaning of unknown words in a second language, learners make use of a variety of cues including the cross-linguistic formal similarities of loanwords and cognates. However, because learners do not always recognize these cross-linguistic relationships, cognate strategy training has been recommended. The present study investigated the impact of cognate strategy training on Japanese speakers’ accuracy when guessing the meaning of unknown English words. The findings revealed that participants were significantly more accurate in responding to cognates after training than prior to it, while responses to noncognates were similar in both rounds. Moreover, participants were more accurate in identifying cognates with common grapheme–phoneme correspondences in English (e.g. fleece) after training than those that had less-common correspondences (e.g. gauge). Considering error rates, the benefit-cost ratio of applying the strategy was four correct guesses to one incorrect guess. Together with insights from a small-scale qualitative follow-up study, the results reveal that both phonological decoding of English words and conversion into katakana script in Japanese contribute to difficulties in noticing cognate relationships. The primary implication of the study is that cognate strategy training may contribute positively to language teaching pedagogy in Japan and other contexts.

在推断第二语言中未知单词的含义时，学习者会利用各种线索，包括外来词和同源词的跨语言形式相似性。然而，由于学习者并不总是能够识别这些跨语言关系，因此建议进行同源策略培训。本研究调查了在猜测未知英语单词含义时，同源策略训练对日语使用者准确性的影响。研究结果表明，与训练前相比，参与者在训练后对同源词的反应明显更准确，而对非同源词的反应在两轮中都相似。此外，参与者更准确地识别英语中常见字素-音素对应的同源词（例如 羊毛）在训练后比那些不太常见的对应（例如仪表）。考虑到错误率，应用该策略的收益成本比是 4 个正确猜测对 1 个错误猜测。结合小规模定性后续研究的见解，结果表明，英语单词的语音解码和日语中的片假名转换都导致了注意同源关系的困难。该研究的主要含义是同源策略培训可能对日本和其他情况下的语言教学教学法做出积极贡献。结果表明，英语单词的语音解码和日语片假名的转换都导致了注意同源关系的困难。该研究的主要含义是同源策略培训可能对日本和其他情况下的语言教学教学法做出积极贡献。结果表明，英语单词的语音解码和日语片假名的转换都导致了注意同源关系的困难。该研究的主要含义是同源策略培训可能对日本和其他情况下的语言教学教学法做出积极贡献。