Complex sentence: Another field Grzegas is involved with is language teaching at the University level, particularly in the development and dissemination of the Learning by teaching model, which was founded in the 1980s by Jean-Pol Martin.
Split into simpler sentences: Another field Grzegas is involved with is the language teaching at the University Teaching. He is particularly involved in the development and dissemination of Learning by teaching model, which was founded in the 1980s by Jean-Pol Martin.