The grammars of signed languages are as highly complex as the grammars of spoken languages and share with them many universal features, despite the difference in modality between spoken languages (which use the auditory channel) and signed languages (which use the visual channel). Yet, sign languages also differ from spoken languages in radical ways: morphological information in sign languages is often conveyed simultaneously by different articulators rather than linearly; moreover, certain aspects of their phonological, syntactic and semantic structures are not commonly found in spoken languages. These differences raise an interesting challenge both for formal linguistic and experimental research frameworks.

FEAST (Formal and Experimental Advances in Sign Language Theory) is the regular forum to discuss formal approaches to sign language grammar (in particular in the generative tradition), experimental approaches to sign languages, and their interaction. FEAST is held as a conference series every one or two years.