This work presents the frontema as a unit created to facilitate the study of phenomena regarding co-articulatory effects in word boundaries. Frontema is the orthographic representation of written language as well as of the acoustic unit corresponding to word boundaries that conventionally form a written text. The concept of frontema, as well as its materialization, simplify the process of discovery of coarticulatory rules, thus contributing to facilitate the prosodic modeling of phrases and, so, reducing the complexity of the process of automatic generation of prosody in systems of speech synthesis by concatenating acoustic units previously recorded.