A major learning difficulty of Japanese foreign language (JFL) learners is the complex composition of two syllabaries, hiragana and katakana, and kanji characters adopted from logographic Chinese ones. As the number of Japanese language learners increases, computer-assisted Japanese language education gradually gains more attention. This study aimed to adopt a Japanese word segmentation system to help JFL learners overcome literacy problems. This study adopted MeCab, a Japanese morphological analyzer and part-of-speech (POS) tagger, to segment Japanese texts into separate morphemes by adding spaces and to attach POS tags to each morpheme for beginners. The participants were asked to participate in three experimental activities involving watching two Japanese videos with general or segmented Japanese captions and complete the Nielsen’s Attributes of Usability (NAU) survey and the After Scenario Questionnaire (ASQ) to evaluate the usability of the learning activities. The results of the system evaluation showed that the videos with the segmented captions could increase the participants’ learning motivation and willingness to adopt the word segmentation system to learn Japanese.