In Brazilian Portuguese, “(eu) acho que” is a construction grammaticalized as a discourse marker with a range of epistemic meanings which may indicate certainty, doubt and uncertainty. Certain linguistic features are associated with each one of them, such as the kind of complement introduced by “(eu) acho que” and the engagement of the speaker (direct, indirect) with what is said. From an acoustic point of view, sentences that indicate doubt and uncertainty have higher values fundamental frequency (F0), intensity, duration, presence of silent or filled pauses, unlike those that indicate certainty. These meanings are also differentiated by body gestures: certainty is characterized by a neutral facial expression, while uncertainty is characterized by the contraction of eyebrows and mouth. We propose an integrative approach among linguistic, prosodic and gestural features, seeking association between these features and the meanings indicated by “(eu) acho que” in Brazilian Portuguese. The effect of linguistic features (type of occurrence, scope, presence of another modal particle, discursive topic, type of experience), acoustic parameters (fundamental frequency, intensity, duration, presence of silent and filled pauses) and facial gestures (movements that indicate anger, mockery, disgust, fear, happiness, neutrality, sadness and surprise) were correlated to the meanings indicated by “(eu) acho que”. Data sample is constituted by 30 sociolinguistic interviews with undergraduates from Sergipe, Brazil (n = 1038). Chi-square tests suggested association between the meaning of “(eu) acho que”, type of occurrence, scope, discursive topic and the engagement of the speakers. For the acoustic variables, analysis of variance indicated a significant effect of intensity and duration: to demonstrate doubt and uncertainty, the pronunciation of “(eu) acho que” was stronger and longer. These two meanings presented gestural correlates: when doubtful and uncertain, the speakers contracted their eyebrows and mouth (movements of expressions of surprise and sadness), results that suggest the potential of studies that include facial gestures in the analysis of inference of meanings.