The current study probes Mandarin-learning toddlers’ sensitivity to two grammatical noun phrase orders differing in typological markedness. With three visual fixation experiments, we find that by age 2;6, children distinguish the cross-linguistically common order – but not the typologically rare one – from an ungrammatical order; however, their sensitivity to the two grammatical orders does not differ significantly. Further, we conduct a corpus analysis and demonstrate that for early acquisition, both grammatical orders are neither sufficiently nor consistently supported in the linguistic input. The sensitivity patterns and input profile outlined in our study constitute the first step of testing, in a natural language setting, a bias for typologically common ordering discussed in the artificial language learning literature. Although the findings remain inconclusive, they underscore the potential for future investigations in this direction.
