Language is primarily constituted by action and interaction based on sensorimotor information. This paper demonstrates the nature of subjectivity and intersubjectivity through the neural mechanism and typological evidence of sentence-final particles from East Asian languages and extends to the discussion of the relationship between them. I propose that intersubjecivity is a kind of embedded or nested interpersonal synergy grounded in mirror neurons. By means of shared motor information and embodied simulation, one’s self models can be generated in which other self-models are embedded. With the process of embedded interpersonal synergies, the relationship between synergies might be concerned to produce mutual shaping of meaning between speaker and hearer. Accordingly, I propose a hypothesis that the more intersubjective markers a language has, the more embedded or nested interpersonal synergies it has. This proposal opens new perspective on the understanding of the nature of language communication and (inter)subjectivity.