Dicta-Sign is a three-year EU-funded research project that aims at making online communications more accessible to deaf SL users. As part of the project, a parallel corpus of recorded signing data was created, using the same elicitation material in four national SL: GSL, BSL, LSF and DGS. The created corpus provides a vast variety of language structures from a significant number of native signers, allowing further investigation of language phenomena in a non-biased, conversational setting that reflects real language use. The annotation of the GSL corpus contributed in the creation of a basic lexicon of the most frequent sings which can serve as the foundation of an extended inventory. The descriptions assigned to the corpus enable a linguistic analysis based on a SL data driven approach. The latter, has up to a certain degree, been employed into the Sis-Builder Sign Synthesis tool, providing impressive avatar-based synthetic SL representations and giving potentials for extended use of this technology in alternative teaching methods.