Speech is normally used for verbal interaction between at least two persons, called interlocutors. Researchers have measured rate of information transfer by speech across languages and have found a relatively constant value across languages. Spoken language is very different from written language in a number of important ways. Speech is perceived by hearers based primarily on the acoustic information contained in the speech signal, but modified by a number of factors, including top--down processing. Perception is made more complex by factors such as the necessity of segmenting and variance in the signal caused by individual differences and conditions of the speech environment. Speaker normalization is required by the hearer. The ear and hearing mechanism play an important role in speech perception. Rapid pressure variation of sound is converted to fluctuations in the viscous fluids of the inner ear or cochlea. This conversion occurs through the middle ear in which the principle of the lever, and the principle of collecting energy over a large area and concentrating it, play roles.

Phonetics is the science explaining what happens as people talk -- that is to say, what happens as we produce the sounds of speech. Speech is a functional part of language, as language is most commonly used in human interaction. Language, in an abstract sense, is something common to all neurotypical humans. This abstract sense of “language” contrasts with specific languages, each one unique. The level of phonetic analysis of language is separate from, but overlapping with, phonology. Phonology focuses more on contrasts, whereas phonetics focuses more on differences. Phonetic variables can be used at very different levels of the grammar in different languages. Traunmüller distinguishes four types of information in speech: phonetic (linguistic), affective, personal, and transmittal. Dialect, register, and the hyperspeech--hypospeech continuum affect specific aspects of phonetic production in a given language. The science of phonetics uses terminology often consisting of ordinary words whose meanings are frequently different from the technical sense.

This chapter addresses the notion of participation by examining it at four different angles of view which we label, in order of roughly widening scope, utterance, talk, event and interaction. We start with the narrowest scope, involving the simplest possible notions of participant role – that of a producer and a receiver. Then, employing and stretching Goffman's notions of footing, production format and participation framework, we gradually widen the scope, putting an ever-increasing amount of flesh on, breaking down into various constituent parts and even questioning the integrity of these bare bones. At the widest scope, there comes a point when the bare bones seem to dissolve, and yet participation with interpersonal and interactive consequences can still be discerned. After proceeding to some considerations of participation in technology-mediated communication, we conclude with some suggestions concerning approaches to the identification of participant roles in the analysis of interaction.

Modal particles occur exclusively in topical contexts. They are excluded in thetic contexts and non-asserted grammatical contexts. They create common ground properties of high speaker-hearer connecting attitudinality with all assets language can provide in terms of manipulation and hyperlinking effects. As modal particles are not restricted to clausal finiteness and assertive contexts, they have a strong contingency in terms of speech acts allowing their occurrence outside of clausal finiteness.