Research on sign languages (SLs) requires dedicated, efficient and comprehensive transcription systems (TranSys) to analyze and compare the sign parameters; at present, many TranSys focus on manual parameters, relegating the non manual component to a lesser role. This article presents Typannot, a formal TranSys, and in particular its application to mouth gestures: i) first, exposing its kinesiological approach, i.e. an intrinsic articulatory description anchored to the body; ii) then, showing its conception to integrate linguistic, graphic and technical aspects within a typeface; iii) finally, presenting its application to a corpus in French sign language (LSF) recorded with motion capture (MoCap).