In analyses of the grammatical structure of sign languages (Liddell, 2003), “classifier forms” which play a major role in these spatialised grammars, are looked upon as a “gestural” component of sign language. Kendon (2004) pointed out that some of the organizational principles of co-verbal gesturing can be compared to “classifiers” in sign languages. In this paper drawing on previous analyses of LIS (Italian Sign Language) metaphors in discourse (Russo, 2004a, 2005) the role of “classifier forms” in SL metaphors is examined and compared with some aspects of gestural metaphors produced during academic lectures in Italian. It is shown that similarities and differences between the two communicative devices can be pointed out only if the multimodal organization of both face-to-face speech activity and face-to-face sign language communication is taken into account. The gestural actions produced by speakers and the non-manual gestures produced by signers are interpreted as framing a speech act unit in this way providing a perspective for the interpretation of the lexical items within it. The distinction between langue and parole proposed by Ferdinand de Saussure (1916) is discussed and reframed by this analysis.