Although linguistic research into the sign languages of established deaf communities has unequivocally shown them to be natural language, there still remains much that is unknown about the appropriate characterization of these languages and in particular their relationships with their host spoken languages. Being based primarily on linguistic (particularly psycholinguistic and sociolinguistic) research in North America on American Sign Language (ASL), research has concentrated on showing the similarity between linguistic patterning in signed and spoken languages. Findings include the establishment and description of: (I) a sign phonology and morphosyntax (the latter particularly rooted in movement, direction and spatial location) and its manifestation in language processing and brain trauma; (II) processes of sign language acquisition parallel to spoken language acquisition; and (III) patterns of language use and cultural identity similar to that of speaking communities. Perhaps due to its roots in North America and the general thrust of much of contemporary linguistics, attention has been focused on a single language function (the ideational function) and how such meanings are encoded in sign languages. In this paper I suggest how the application of the principles of systemic functional linguistics help identify and describe the grammatical resources of visual-gestural languages in constructing and conveying meanings.