The use of indirect language is considered useful for persuading people in human communication. The aim of this research is to determine whether this also occurs within human-robot interaction. Thus, it is hypothesized that indirect language will have greater influence in attitude changes towards a product in comparison to direct language. A seven-point semantic differential scale was employed to measure participants attitude changes towards a product advertised by a Nao Robot using either direct or indirect speech. Results showed no significant differences between the direct and indirect language experimental conditions. This may indicate that in human-robot interaction indirect language may not function similarly as it does in human communication. A larger sample size and improvements in stimuli are suggested for future works.