Although parental language and behaviour have been widely investigated, few studies have examined their unique and interactive contribution to the parent-child relationship. The current study explores how parental behaviour (sensitivity and non-intrusiveness) and the use of parental language (exploring and control languages) correlate with parent-child dyadic mutuality. Specifically, we investigated the following questions: (1) 'Is parental language associated with parent-child dyadic mutuality above and beyond parental behaviour?' (2) 'Does parental language moderate the links between parental behaviour and the parent-child dyadic mutuality?' (3) 'Do these differences vary between mothers and fathers?' The sample included 65 children (Mage = 1.97 years, SD = 0.86) and their parents. We observed parental behaviour, parent-child dyadic mutuality, and the type of parental language used during videotaped in-home observations. The results indicated that parental language and behaviours are distinct components of the parent-child interaction. Parents who used higher levels of exploring language showed higher levels of parent-child dyadic mutuality, even when accounting for parental behaviour. Use of controlling language, however, was not found to be related to the parent-child dyadic mutuality. Different moderation models were found for mothers and fathers. These results highlight the need to distinguish parental language and behaviour when assessing their contribution to the parent-child relationship.