This article describes an archaeology lesson designed, through a cultural linguistic approach, to teach the English modal + have + past participle construction and the basics of archaeological reasoning to Japanese learners. Evidentials are among the most difficult forms for L2 English learners to master. For Japanese learners, a precollege educational format that emphasizes memorization of objective facts further hampers understanding and use of English evidentials. Both English and social science education in Japan are presented under this test-focused approach. Moreover, archaeological reasoning is presented differently in Japanese- and English-speaking contexts. The cultural linguistic approach provides a basis for understanding why this aspect of L2 English is difficult for Japanese learners and supports the development of effective curricula.