Abstract
There are some examples of rentaikei endings and rentaikei+yo endings with mu, ramu, or kemu (the mu-type auxiliary verbs) in the predicate position to express speculation or preference. These are divided into the following two categories. Category 1: Expressing a future situation unrelated to speculation or preference regarding the language agent. Category 2: Expressing an existing situation that is inconsistent with the expectation of the language agent. The future situation given in Category 1 exists only in the imagination of the language agent. In contrast, the language agent in Category 2 is confused by the situation that differs from expectations and imagines its existence once again. From the above, we conclude that these mu-type auxiliary verbs in Categories 1 and 2 have the function of "imagining a situation existing in the real world" (conceptualization).
