In this paper, our research studies on prosody variation modeling are introduced for communicative prosody characterization and the objective evaluation of the second language (L2) timing control characteristics. For communicative prosody characterization, a possibility of lexicon driven control and further needs of dialogue-act modeling are discussed. For the objective evaluation of L2 prosody, the possibility of scientific understanding of timing control characteristics and the needs of perceptual studies are demonstrated. Through the introduction of these studies, I would like to show the necessity and the merits of transdisciplinary research collaboration among multiple research areas relating to speech science and technologies including linguistics, phonetics, speech science, information processing, and language education. Finally, the research efforts are introduced for international research consortium AESOP (Asian English Speech cOrpus Project) to collect commonly sharable learner's spoken language data and knowledge of L2 studies for trans-disciplinary scientific understanding.