So far all the studies which have been published on Chichewa tones have dealt with the Malawian variety of the language. There is no published information available on the tones of Chinyanja spoken in Zambia and Mozambique. In order to understand Chichewa tones, it is necessary first to understand various tonal phenomena that can occur, which are briefly outlined below. Normally in a Chichewa sentence, whenever tones come in the sequence HLH or HLLH, it is usual for the second high tone to be a little lower than the first one. So for example in the word 'I usually go', the tone of the syllable is pronounced a little higher than the tone of . Thus generally speaking the highest tone in a sentence is the first one. This phenomenon, which is common in many Bantu languages, is known as 'downdrift' or 'automatic downstep'. However, there are several exceptions to this rule. Downdrift does not occur, for example, when a speaker is asking a question, or reciting a list of items with a pause after each one, or sometimes if a word is pronounced on a high pitch for emphasis. There is also no downdrift in words like 'policeman', where two high tones in the sequence HLH are bridged to make a plateau HHH (see below). In some dialects a high tone may sometimes spread to the following syllable; this is known as 'High Tone Spreading' or 'Tone Doubling'. So where some speakers say 'I helped', others will say . Some phoneticians argue that what happens here, in some cases at least, is that the highest part or 'peak' of the tone moves forward, giving the impression that the tone covers two syllables, a process called 'peak delay'. An illustration of peak delay can be seen clearly in the pitch-track of the word 'they fed', here pronounced , in Downing et al. (2004). In order for HTS to occur, there must be at least 3 syllables following the tone, although not necessarily in the same word. One very frequent use of spreading, at least in some dialects, is to link together two words (such as verb + object, or verb of motion + destination, or noun + possessive) into a single phrase. In transcriptions one frequently finds phrases such as 'to cook meat' or 'to care for a wife', 'my maize' 'those lions' etc. in which the second tone in each phrase is not original but due to spreading.