stress). For example, the word amazing has primary stress on the second syllable, while the first and third syllables are unstressed, whereas the word organization has primary stress on the fourth syllable, secondary stress on the first, and the second, third, and fifth unstressed. This is often shown in pronunciation keys using the IPA symbols for primary and secondary stress (which are ˈ and ˌ respectively), placed before the syllables to which they apply. The two words just given may therefore be represented (in RP) as and . Some analysts identify an additional level of stress (tertiary stress). This is generally ascribed to syllables that are pronounced with less force than those with secondary stress, but nonetheless contain a "full" or "unreduced" vowel (vowels that are considered to be reduced are listed under above). Hence the third syllable of organization, if pronounced with as shown above (rather than being reduced to or ), might be said to have tertiary stress. (The precise identification of secondary and tertiary stress differs between analyses; dictionaries do not generally show tertiary stress, although some have taken the approach of marking all syllables with unreduced vowels as having at least secondary stress.) In some analyses, then, the concept of lexical stress may become conflated with that of vowel reduction. An approach which attempts to separate these two is provided by Peter Ladefoged, who states that it is possible to describe English with only one degree of stress, as long as unstressed syllables are phonemically distinguished for vowel reduction. In this approach, the distinction between primary and secondary stress is regarded as a phonetic or prosodic detail rather than a phonemic feature – primary stress is seen as an example of the predictable "tonic" stress that falls on the final stressed syllable of a prosodic unit. For more details of this analysis, see Stress and vowel reduction in English. For stress as a prosodic feature (emphasis of particular words within utterances), see below. Phonotactics Phonotactics is the study of the sequences of phonemes that occur in languages and the sound structures that they form. In this study it is usual to represent consonants in general with the letter C and vowels with the letter V, so that a syllable such as 'be' is described as having CV structure. The IPA symbol used to show a division between syllables is the full stop . Syllabification is the