Language ambiguity results from, among other things, the vagueness of the syntactic structure of phrases and whole sentences. Numerous types of syntactic ambiguity are associated with the placement of the phrase boundary. A special case of the segmentation problem is the phenomenon of word boundary ambiguities; in spoken natural language words coalesce, making it possible to interpret them in different ways (e.g., a name vs. an aim). The purpose of the study was to verify whether the two meanings of words with boundary ambiguities are activated, or whether it is a case of semantic context priming. The study was carried out using the cross-modality semantic priming paradigm. Sentences containing phrases with word boundary ambiguities were presented in an auditory manner to the participants. Immediately after, they performed a visual lexical decision task. Results indicate that both meanings of the ambiguity are automatically activated — independently of the semantic context. When discussing the results I refer to the autonomous and interactive models of parsing, and show other possible areas of research concerning word boundary ambiguities.