Usami, Keiko. (2013). Experimental research for instruction of the Japanese conjunction de: The effectiveness of input flood, input enhancement, and explicit grammar explanation. Acquisition of Japanese as a Second Language. 16, 196-213. [Article written in Japanese]
This study examined the effects of instruction on the learning of the Japanese conjunction de. Three different treatments were employed: 1) input flood (Flood Group), 2) input flood plus input enhancement by the use of subtitles (Enhancement Group), and input flood, input enhancement plus explicit grammar explanation (Explicit Group). Outcomes of these treatments were compared in a controlled experimental study involving 55 students of Japanese. The effects were measured utilizing a pre-test, post-test, and a delayed post-test using a narrative task. The results indicated that the
explicit grammar explanation had the most significant effect on the learning of the
Japanese conjunction de.