Three experiments tested the role of an emerging syntactic tone in spoken word recognition of Beijing Mandarin Chinese. The study examined the role of the new syntactic tone in lexical access and how synchronic change is perceived in the task of word recognition. Experiment 1 used an information-deprived condition where information for the standard interpretation of the word was provided prior to the crucial tone, but the syntactic tone based interpretation was not provided. Experiment 2 used a prosody-reduced condition where the prosodic cues were unclear while information for both standard and syntactic tone based interpretation was provided. Experiment 3 involved a story retell task to further assess tone comprehension. The results show that the emerging syntactic tone had an impact on participant's lexical interpretations, although the impact was more obvious when prosody information was clearly provided. The results also confirmed participants' tone comprehension through story retells. The results support the hypotheses that a) there is a new syntactic tone in spoken Beijing Mandarin whose function goes beyond lexical tone, which has become a precursor for word recognition in discourse processing; and, b) language processing reflects asymmetry in that speakers prefer the traditional grammatical interpretation more than the interpretation derived from the newly developed syntactic tone when prosodic information is unclear. The study demonstrates how usage-based grammatical changes affect speaker's mental model of lexical access.