This study reports the results of an interpretation task that captures whether high proficiency heritage language (HL) learners of Russian converge with monolingual (L1) speakers or proficiency-matched foreign language (L2) learners in their interpretation of aspectual pairs and whether the absence of convergence arises in the lexical component of aspect ("telicity") or in the grammatical component of aspect ("boundedness"). In Russian, both aspectual features are overtly marked on the verb, but by different morphemes: telicity is encoded in prefixes and boundedness in suffixes. The goal of the task is to test: 1) whether HL learners have an advantage over L2 learners on the same overall proficiency level when they interpret aspectual pairs, 2) which type of aspectual contrast poses greater difficulty, and 3) what role the morphological structure of predicates plays in incomplete acquirers' interpretation of verbal aspect. The results reveal that, while the L2 group and the monolingual controls diverge significantly in most contrasts, the HL group converges with both L1 and L2 groups. For both test groups, telicity contrasts in activity/accomplishment verbs, which are expressed via prefixation, and boundedness contrasts in achievement verbs, which are expressed via suffixation, presented less difficulty than boundedness contrasts in accomplishment verbs, expressed via both prefixation and suffixation. (Contains 4 tables, 6 figures, and 5 notes.)