This paper focuses on the investigation of the meaning of reduplication in Brazilian Sign Language (Libras) analyzing the contribution of each of its forms: repetition (\rep) and alternation (\alt). In order to check their role, we proceeded a data collection with a native signer during elicitation sessions following the methodology for semantic elicitation (Matthewson, 2004). We also collected a spontaneous datum with another signer. We show that \rep is related to aspectual distribution, and \alt is associated to two pieces of information - participant-related distribution and aspectual distribution. We propose a formal analysis for each of the forms as well as of the way they interact compositionally.