The foundation of communication that transcends subjectivity and objectivity. In the age of AI, cultural psychologist Kim Jung-woon reveals the secrets of human interaction to restore the 'intersubjectivity' we have lost. We generally understand communication as the skill of 'speaking well.' It involves choosing the right words, constructing logic, and persuading others. But is that really the case? A newborn baby does not yet know words or how to form sentences. Yet, after a few months, they laugh, cry, wait, and respond with others. As time passes, they begin to follow others' gazes, infer their feelings, and try to convince others of their thoughts. What happens to the baby during this short time? When do we become beings capable of 'understanding' each other, and through what means? This book starts from that ancient and fundamental question. "Speaking Without Words" traces the origins of communication outside the familiar framework of 'sender-message-receiver.' According to the author, the starting point of human communication is not sentences, information, or logic. What comes first is the body. 'Touch,' where skin meets skin, 'eye contact' that acknowledges each other's existence, 'emotional attunement' that intersects emotional rhythms, 'turn-taking' that operates before speaking, 'joint attention' where two people simultaneously focus on one object, and 'perspective shifting' that reconstructs the world through another's gaze. These six elements are not mere developmental stages; they illustrate how humans form the experience of 'we' beyond the separation of 'I' and 'you.' The most significant feature of this book is that it does not treat non-verbal communication merely as a supplementary means of conveying information or expressing emotions. The author traverses cultural psychology, developmental psychology, and intersubjectivity research, reinterpreting Vygotsky's insight that even higher mental functions arise between people and are later internalized within individuals. The self is not given in isolation from the beginning; it is formed as interactions with others seep into the inner self. Therefore, communication is not merely messages exchanged between already complete individuals, but rather a pre-existing event that shapes the individuals themselves. This book compellingly reconstructs that scene, tightly weaving together everyday examples and sophisticated psychological research. Empathy over persuasion, joint attention over fluent speech. A communication method of admiration and respect where sensations intersect. Focusing on the hidden key to relationships, intersubjectivity. Mothers around the world invariably say the same thing to their newborns: "Oh, who did that? Who did that?" It is unclear what is being asked and by whom. Yet, this phrase is not unique to Korean. "Who did that?" (English), "Qui a fait ça?" (French), "Wer hat das gemacht?" (German), "だれがやったの" (Japanese) - despite the different languages, the structure of what mothers say to their babies is the same worldwide. According to developmental psychologists Daniel Stern and Colwyn Trevarthen, this phrase is not actually a question. The intonation of 'who?' itself serves as a social signal that "you need to respond to this rhythm right now." Human communication begins in this pre-verbal rhythm. However, we have forgotten this fact for too long. Most theories of communication have taken the 'linear model' of a sender conveying a message to a receiver as a given. As a result, Claude Shannon's theory, which laid the foundation for digital information engineering, has solidified as the standard model of human communication. 'Meaning' has disappeared, leaving only 'information.' German social philosopher Jürgen Habermas pointed out the fatal flaw of this model early on. True communication is not about the accurate transmission of messages, but rather a 'process of intersubjective meaning formation' where participants examine the validity of each other's claims and reach consensus. However, empirical foundations to support that claim have long been absent. "Speaking Without Words" fills this gap. Cultural psychologist Kim Jung-woon reconstructs the rediscovered Vygotskian psychology, mirror neuron research, and recent studies on intersubjective communication in a contemporary context, drawing a comprehensive map of human interaction. Insights from thinkers spanning East and West, such as Vygotsky, Stern, Tomasello, Harvey Sacks, Habermas, Kahneman, Hegel, and Kant converge into a coherent logic here. Communication is not about exchanging messages; it is a process of jointly constructing an 'intersubjective world' between two people. Touch: What have we lost in a society where physical contact has disappeared? Touch is not merely a sensory stimulus. It is the first way that 'I' as an entity is confirmed by others. The author demonstrates through various studies the impact of skin contact on oxytocin secretion and trust formation, as well as the effects of kangaroo care for newborns on development, showing that touch is the biological foundation of communication. Masked expressions, meetings replaced by non-face-to-face interactions, and words pouring through smartphones - we touch our smartphones every day, but the physical warmth that confirms each other's existence is absent. The first condition of communication is quietly crumbling. Eye contact: The gaze is the heart. The human eye is uniquely developed among primates, with a prominent sclera (the white part of the eye). It has evolved to expose the direction of gaze to others. This design, which does not hide 'what I am currently looking at,' serves to signal that we are looking at the same thing together. Eye contact is not merely the act of looking at each other; it is an act of acknowledging the other as a person. The moment a mother and baby make eye contact, a conversation that predates language begins between them. Emotions are conveyed through gaze, existence is confirmed, and the grammar of relationships is formed. Emotional attunement: Emotions are not felt alone. Developmental psychologist Daniel Stern discovered a remarkable scene while analyzing the interactions between mothers and babies frame by frame. When a baby shakes a toy and exclaims, "Ah!", the mother responds by swaying her body back and forth in the same rhythm. It is not merely mimicking sound with sound; it is about aligning the emotional waves by intersecting rhythm, intensity, and form. Stern called this 'sensory emotion,' and he viewed this intersubjective emotional exchange as the foundation for self-formation and understanding of others. The author elevates this concept of 'emotional attunement' to the core of communication theory. During the COVID-19 pandemic, how emotional attunement broke down among masked individuals and why participants' emotions quickly depleted in video conferences - communication fatigue arises not from information overload but from the failure of emotional attunement. Furthermore, the author does not see this 'cross-modal imitation of sensory forms' as merely a developmental concept for infants. The reinterpretation of already existing objects in the language of different senses, termed 'cross-editing of senses,' is the essence of human creation, which is the most provocative claim of this book. The synesthetic experiments practiced by the German Bauhaus, where one 'hears colors and sees sounds,' emerge not as innate abilities of individuals but as products of intersubjective practices. Turn-taking: Conversation is a miracle of 0.2 seconds. Sociologist Harvey Sacks discovered a peculiar fact while analyzing recordings of phone consultations at the Los Angeles Suicide Prevention Center in the 1960s. People seemed to be chatting without any rules, but in reality, they were precisely coordinating who would start and stop speaking when. Subsequently, Sacks and his colleagues discovered the 'turn-taking' system of human conversation after more than ten years of research. A 2015 study by Levinson and Torreira confirmed this revolution. The average time it takes to switch turns in human conversation is only 0.2 seconds. This means that individuals are already preparing their responses before the previous speaker has finished. This is not merely a reaction; it is a 'predictive collaborative behavior' that occurs while anticipating the other person's intentions in real-time. Even the most sophisticated AI models fail to replicate this 0.2-second turn-taking. Human conversation is the product of millions of years of evolution. Joint attention: Civilization began with looking up at the sky together. At nine months old, a decisive cognitive revolution occurs in babies. Until then, they primarily looked at their mother's face, but now they follow her gaze when she turns her head. This is the moment they first recognize 'the other as an intentional being.' Evolutionary anthropologist Tomasello calls this the 'nine-month revolution.' This ability does not exist in chimpanzees. Babies immediately follow the gaze of another person even if their head is still, while chimpanzees do not respond at all to the direction of gaze. The author believes this difference explains the entirety of human civilization. Constellations were formed, myths were born, and civilizations were constructed based on this ability to 'look together.' This simple ability to follow another's gaze is the starting point of abstract thinking and imagination. Perspective shifting: The only way to escape the narrative of victimhood. The final part of the book is the most challenging. The author interprets Korea's hottest issues - victim narratives, fandom politics, and the MBTI craze - as failures of perspective shifting. The Korean word '억울함' (meaning a sense of injustice) does not translate into foreign languages. This word contains three intertwined meanings: 'I did nothing wrong,' 'I was treated unfairly,' and 'I feel frustrated and helpless.' The author diagnoses that this emotion is deeply imprinted in the collective psyche of Koreans through colonial experiences, war, and rapid growth, relating to the 'outsourcing of self' - a structure where self-esteem is based on the recognition of others. The moment one becomes a victim, the mind feels at ease. Victims are weak, but they are morally right. However, this sense of relief demonizes the other and makes true communication impossible. Perspective shifting is the cognitive courage to dismantle this mechanism of demonization. Admiration - the ultimate purpose of communication. In the appendix, the author presents a single theme that runs through the six keywords. We live to admire and to be admired. Through Hegel's struggle for recognition, Kant's sublime, and Elias's process of civilization, the author delicately distinguishes between recognition, admiration, and respect. Recognition is approval through the intellect, while admiration is the moment that approval comes alive in the body. Respect is the grammar that makes admiration possible. AI can endlessly generate words of recognition and praise. However, it cannot truly admire. The ultimate purpose of communication lies in that moment of admiration, an intersubjective experience where the body responds to the existence of others. In a time when social media is overflowing with predatory attention and algorithms fill the space of perspective shifting, this book asks: Are we truly communicating? In the absence of things that must be accomplished before speaking, what are we losing? Above all, the reason this book is urgently needed at this moment is that while we are more connected than ever, we are rapidly losing the foundations of communication. We touch our smartphones, but the warmth of others' bodies is gone; we gaze at each other, but respectful eye contact has diminished; and algorithms have transformed the experience of looking together into predatory attention and immediate anger. AI skillfully mimics human speech patterns, but it lacks the sense and history of the 'things that must be said before speaking.' "Speaking Without Words" is an attempt to restore that disappearing space, the most archetypal layer of human communication. In an era overflowing with information but devoid of understanding, this book returns to the beginning and asks: What have we truly used to understand each other? And what must we reclaim now to avoid losing that ability? "Speaking Without Words" is a book born at the intersection of psychology, philosophy, and cultural theory. It coexists with academic rigor and the author's unique sharp humor, translating the developmental psychology of Vygotsky and Tomasello into the language of Korean politics, workplace culture, and human relationships. It will serve as the most fundamental cultural psychology lesson for those who repeatedly fail in relationships.