One of the most popular services offered by the Internet nowadays is Internet Relay Chat (IRC). IRC allows a large group of people to exchange messages anonymously in real time. The users should follow some rules and principles to carry on successful “talk” in chat.

Chat interaction can be defined as a kind of everyday dialogue built according to specific principles.
A number of linguistic and extra-linguistic chat-interaction peculiarities were revealed while comparing oral everyday conversation and “human-computer-human” dialogue. They include:

• grammatical peculiarities: omission of auxiliary parts of speech (articles, particles, prepositions); different types of ellipsis in nearly all sentences, including omission of the main members of the sentence;
• spelling peculiarities: a great number of misspellings, substitution of word parts by homophones; absence of initial word capitalization in sentences;
• punctuation peculiarities: (complete or partial) lack of punctuation marks, including full stops; irregular use of blanks;
• lexical peculiarities: a great number of abbreviations to speed up interaction; extensive use and coinage of Internet jargon determined by the nature of a particular chat-room.

Extra-linguistic peculiarities of chat-interaction include the following objective and subjective factors:

• visual factors: absence of kinetic communication; verbalizing one’s emotions and use of emoticons or emotional abbreviations;
• the time factor, largely determining linguistic peculiarities;
• subjective factors: lack of information about one’s partners’ identity, e.g. social status, profession, age, sex, etc.; taking for granted whatever input is provided; a possibility of creating any image of oneself.

Therefore, EFL and especially ESP teaching requires not only traditional grammar knowledge, but also awareness of chat-dialogue peculiarities.