Tones are used in particular sequences (patterns) to express a wide range of meanings. There are several clearly discernable intonation patterns that are used on a regular basis in English. They are called basic because
1 they can be contrasted to one another both in form and meaning, i.e. the replacement of one pattern by another causes a change in the meaning of an utterance;
2 they are typical, i.e. they are pronounced and used in much the same way by all the educated English-speaking people;
3 they refer to an independent utterance, i.e. correspond to one intonation group.
Basic intonation patterns (BIP) of English are traditionally presented as pitch patterns, pitch being regarded as a decisive component in the description of intonation. According to the directional type of nuclear pitch change BIPs are divided into 4 main groups, the Falling tone pattern, the Rising tone pattern, the Falling-Rising tone pattern, and the Rising-Falling tone pattern. Each patterns in its turn includes several contours. For example, the Falling pattern is further subdivided into 1 the High (Stepping) head + Mid Wide Fall contour; 2 the High (Stepping) head + High Wide Fall contour; 3 the Low Head + Low Narrow Fall; 4 the Sliding head + Mid Wide Fall contour, etc.