This article presents a formal semantic account of the ambiguity associated with the -te iru construction in Japanese. This construction is known to receive at least two distinct interpretations: on-going process interpretations analogous to the English progressive and so-called resultative interpretations. The latter are sub-classified by some researchers into concrete result state readings and experiential state readings. Based upon the distributional properties of adverbials, we suggest that progressive interpretations of DURATIVE VERBS and concrete result state interpretations of INSTAN- TANEOUS VERBS should be grouped together, as opposed to experiential readings of DURATIVE or INSTANTANEOUS VERBS. To account for the distinction between these two types of interpretation, the proposed system analyzes the -te iru form into the morpheme -te, which is claimed to bear a perfect feature, and the aspectual auxiliary iru. Our proposal for the aspectual auxiliary iru is an extension of Landman’s (1992) proposal and offers a unified account of the multiple interpretations of -te iru on the basis of a new analysis of INSTANTANEOUS VERBS. 1. INTRODUCTION In this article, we will discuss the semantics of the -te iru form in Japanese and propose an account of its multiple interpretations in a formal semantic framework. Kindaichi (1950) points out that the -te iru form in Japanese is ambiguous between two interpretations. Consider the following examples: (1) a. Taroo-wa ima ie-o tate-te iru. Taro-Top now house-Acc build-TE IRU-Pres ‘Taro is now building a house.’ b. Hito-ga asoko-de sin-de iru. 1 person-Nom there-at die-TE IRU-Pres ‘There is a body there.’ (Lit.: ‘A man is dead there.’) If we assumed that the -te iru form in Japanese has exactly the same meaning as the English progressive, we would predict that (1a–b) translate into English as (2a–b). (2) a. Taro is building a house. b. A man is dying. Both (1a) and (2a) have an on-going process interpretation and fail to entail that Taro will eventually finish building a house. On the other hand, TOSHIYUKI OGIHARA Journal of East Asian Linguistics 7, 87–120, 1998.  1998 Kluwer Academic Publishers. Printed in the Netherlands. THE AMBIGUITY OF THE -TE IRU FORM IN JAPANESE