This paper analyzes synesthetic expressions on language in Japanese from a cognitive linguistic point of view. Visual expressions are the most common in Japanese. “Miru (look)”, “mieru (seem)”, “katati (form)”, “sugata (shape)”, “marui (round)”, “sikakui (square)”, “iro (color)”, “akarui (bright)”, “kurai (dark)”, “hikari (light)”, “yami (dark)”, “kireida (pretty)”, “utukusii (beautiful)”, “kitanai (dirty)”, “minikui (ugly)” etc. are used. There are not many auditory expressions. “Hibiku (resonate)”, “narihibiku (ringing back)” etc. are used. Also, there are not many olfactory expressions. “Nioi (odor)”, “kaori (scent)”, “kagitoru (sniff)” etc. are used. Taste expressions are relatively common. “Azi (taste)” “aziwau (taste)”, “amai (sweet)”, “karai (spicy)”, “siokarai (salty)”, “nigai (bitter)”, “suppai (sour)”, “sibui (astringent)” etc. are used. Somatosensory expressions are divided into tactile expressions, thermal sense expressions and painful sense expressions. As tactile expressions, “kansyoku (tactile)”, “situkan (texture)”, “tezawari (touch of hand)”, “hadazawari (touch of skin)”, “katai (hard)”, “yawarakai (soft)” etc. are used. As thermal sense expressions, “netu (heat)”, “taion (body temperature)”, “atui (hot)”, “atatakai (warm)”, “tumetai (cold)” etc. are used. As painful sense expressions, “itai (painful)” and similar words are used. Synesthetic expressions are metaphors widely used in ordinary language, and also for discussing language itself. Naturally, spoken language is recognized by the auditory sense, and written language is recognized by the visual sense. But there are also synesthetic expressions that correspond to nothing in reality. We can say that synesthesia plays an important role in human cognitive activities.
