Buddhist thought conceives of language as the main tool to build and articulate phenomenal reality. The fourth ring in the chain of conditioned causation (pratitya-samutpada), nama-rupa, represents the inextricable interdependence of cognitive processes and external reality, phenomena and discriminating mind, names and things of the ordinary world of suffering. 

Linguistic descriptions of the world have no absolute truth value; language is an instrument of fallacious knowledge, because it creates the reality perceived in ordinary states of consciousness, through the categorization and conceptualization of perceptual data and their semantic articulation. 

Ordinary yogacara epistemology, which takes the shape of a radical constructivism, attributes to language the function of articulating a world of illusion through the power of semiotic "seeds" (bija). Non-enlightened people consider their own ordinary image of the world to be true and corresponding to reality, since they attribute to the objects the characteristics peculiar to linguistic expressions (autonomy, immutability, homogeneity). 

This kind of confusion of ontology with epistemology, of reality with its linguistic descriptions and mental images is called avidya, "ignorance". Epistemologic ignorance is the first cause of existential suffering. Therefore, there is an absolute hiatus separating language from true reality. The tradition of the great Indian philosopher Nagarjuna (ca. 150-250 A.D.), in particular, systematically developed this philosophical position. 

According to a well established traditional doctrine, quoted in some Buddhist sutras, the words of ordinary language are (i) related to superficial aspects of phenomena, (ii) uttered in dreams (iii) conditioned by fallacious attachment to wrong ideas, (iv) forever conditioned by the seeds of suffering. 

Being this the case, Buddhist linguistic speculation had to face the question of the status of the word of the Buddha. Did the Buddha contribute to sentient beings' suffering and illusion speaking words devoid of truth? 

As one can easily understand, this was not just a pedantic disquisition on the edges of philosophy of language. On the contrary, doctrinal matters of pedagogy, epistemology and soteriology were at stake here, affecting also speculations on the nature of the Buddha and the status of his historical and provisional manifestations. 

Obviously, it was not possible to completely deny the value of the word of the Buddha, because this would have meant the self-destruction of Buddhism. Instead, a distinction was made between the wisdom of the Buddha and the signs conveying it, and the word of the Buddha was given a peculiar status. Texts like the Diamond Sutra (Vajracchedika Prajnaparamita Sutra), the Vimalakirti Nirdesa Sutra, or the Lankavatara Sutra sanction in an inevitably paradoxical way the ineffability in human ordinary language of the wisdom of the Buddha. 

This sanction of ineffability can be interpreted in two ways, both very interesting for the semiotician: 
i) the Buddha does not speak, and conveys his experience in a non-linguistic way, because communication through language is not possible; this view was later developed in particular by some chan and zen radical currents, which rigorously attempted to deconstruct and dissolve every semiotic practice; 
ii) the Buddha, on the basis of his states of consciousness, uses a peculiar language consisting in special systems of signs, which is possible to know and understand. 

These opposite positions both presuppose a theory of communication and a semiotics of initiatory transmission of meaning. Despite doctrinal differences, all Buddhist traditions in fact agree with some basic hermeneutical assumptions, according to which the Buddha explained many different doctrines in consideration of circumstances and contexts of speech, and competence and salvational needs of the audience. 

The first sanction of ineffability (communication through language is impossible) was developed by the tradition ascending back to Nagarjuna, aimed at the attainment of the Emptiness through the incessant deconstruction of assumptions, concepts, meaningful practices. 

The second option (the Buddha speaks a different, higher kind of language) could yield on its turn to two different interpretations: 
(a) the language of the Buddha is a mere upaya, a skilful means, an expedient devoid of absolute value but necessary in order to help the humans to attain a truth transcending every language: this is the doctrinal position of most Buddhist schools; 
(b) absolute truth can be communicated, and the Buddha speaks peculiar words of a non-ordinary language in order to lead sentient beings to salvation: this is the basic assumption of the teachings of esoteric Buddhism. 

In both cases, a systematic manipulation of linguistic signs was put into practice, in order to bring language beyond its limits, and force it to speak the absolute. 

How is communication explained by Buddhism? What are the characteristics of signs? What are their status and functions? In which ways does semiosis — the cultural practice of creation and interpretation of signs, and transmission of knowledge — occur? And further: which are the strategies concerning the discursive transposition of Buddhist religious experience? What kind of relationship connects cosmology, ontology, soteriology, and semiotic concepts and practices within the Buddhist episteme? All these questions are relevant both to general semiotics as a theoretical discipline and a philosophical activity, and to the interpretation of cultures in which Buddhism developed as well, since Buddhist philosophical reflection on sign and the related practices probably constituted their predominant semiotic paradigm (or, at least, part of it) for many centuries. 

An organic and systematic study of Buddhist semiotics is still to undertake. Until now, only a few scholars tackled aspects of Buddhist cultures with a semiotic eye: among them Allan Grapard, Stanley Tambiah, Alexander Piatigorsky, Gregory Schopen. 

Buddhist semiotic ideas and practices show many differences, for they developed in a wide variety of cultural, historical, and social contexts. Buddhism established two basically different kinds of semiotics: one related to what could be called ordinary semiosis, another to describe the interactions with reality in altered (meditative) states of consciousness. Only the most basic elements of Buddhist semiotics, common to a large part of the Buddhist universe of discourse, will be outlined here. 

One of the most striking characteristics of the Buddhist Canon is its heterogeneity; even the doctrines traditionally attributed to the teaching of the historical Buddha are often in overt contradiction. The Buddhists gave such doctrinal heterogeneity a pragmatic and communicational meaning. One of the cores of Buddhism, in fact, is that the Buddha taught many different doctrines according to his audience's faculties and possibilities of comprehension. This is in accordance with Indian cosmology and psychology, which recognize various levels of existence and stages in the development of consciousness: a certain truth and a certain set of doctrines correspond to each one. Therefore, Buddhist exegesis presupposes some interesting points for the semiotician: different levels of truth, and a semiotics of textual cooperation. 

In Mahayana Buddhism the Buddha is no longer simply a historical person, the teacher, the Enlightened One, but is transformed into a manifestation of the universal principle of enlightenment, a silent, eternal, numinous presence, called Dharmakaya ("the body of the Dharma"). This buddhologic transformation made the Universal Buddha the ultimate subject of all discourses, the universal principle of articulation of discursivity. This is shown in many texts, where the Buddha says nothing until the epilogue, but silently empowers the characters of the text to ask and answer, thus revealing themselves certain difficult doctrines. 

Perhaps the most influential Buddhist model of semiosis was developed within the Indian yogacara epistemologic tradition by Asanga (IV century), Vasubandhu (IV-V century), and later by Indian, Chinese, Korean, Japanese, and Tibetan monks. The principle of this school was very subtle and complicated, its basic tenets can be outlined as follows: 

According to yogacara epistemology, semiosis (and knowledge) is a complex process of interaction between various levels and functions of mind with a supposedly outside world through the mediation of senses. Each one of the six sense organs (sight, hearing, taste, smell, touch, intellect) perceives qualities among six perceptual fields in the outside world (forms, sounds, flavours, perfumes, tactile qualities, the thinkable). Perceptual data of direct experience (preceding the attribution of a name) are further elaborated by six sense consciousness corresponding to each of the six sense organs; in particular, the sixth consciousness unifies the data, attributes names and formulates judgements.