Unlike Standard English, one in Singapore Colloquial English (SCE) not only functions as a numeral and a pronoun, it also functions as a nominalizer and a contrastive focus marker. Even though previous studies on SCE one have unequivocally proven that the expanded functions of one were a result of Chinese influence, few have provided an explanation for the non-transferability of the nominal modification marker function. Based on Heine & Kuteva's (2005) theory that contact-induced grammaticalization conforms to the principles of grammaticalization, this paper argues that an alternative reason why certain functions of Chinese de were not transferred into SCE is due to an absence of ambiguous or bridging contexts, which are mediating conditions for grammaticalization to take place. A detailed analysis of Chinese and English data clearly demonstrates how similarities between one and de create ambiguity in the input of SCE, thereby allowing one to grammaticalize via the mediation of bridging contexts.