There is only one minimal pair to illustrate the contrast in distribution: núhuʼ, "this" versus níhiʼ-, "X was done with Y", in which níhiʼ- only occurs in bound form. Remarkably, unlike more than 98% of the world's languages, Arapaho has no low vowels, such as . In addition, there are four diphthongs, , and several triphthongs, as well as extended sequences of vowels such as with stress on either the first or the last vowel in the combination. The consonant inventory of Arapaho is given in the table below. When writing Arapaho, is normally transcribed as , as , as , and as . The phoneme /b/ (the voiced bilabial stop) has a voiceless allophone [p] that occurs before other consonants or at the end of a word. The plosives , /k/, and /t/ are pronounced without aspiration in most environments, but are aspirated before other consonants or at the end of a word, or when preceding a syllable-final sequence of short vowel + /h/. In this same environment /b/ is aspirated and devoiced. For example, the grammatical prefix cih- is pronounced , the grammatical prefix tih- is pronounced , and the word héétbihʼínkúútiinoo, "I will turn out the lights" is hetihʼínkúútiinoo. Syllables tend to have the structure CV(C), where the final consonant, if it is present, is either a single consonant, or /hC/. In general, consonant clusters in Arapaho can only be two consonants long. Consonant clusters do not occur word initially, and /hC/ is the only that occurs word finally. The only consonant cluster that is "base generated" (exists in the most underlying representation of words) is /hC/. At the "surface" (at the level of actual pronunciation), other clusters arise by phonological processes including vowel syncope, or by juxtaposition of morphemes. Vowel-initial, onset-less syllables, however, can occur due to partitioning of vowel clusters. An example of partitioning a cluster of 3 identical vowels into syllables is ní.ii.non, "tepee." The vowel cluster is not always split into short vowel followed by long vowel; the location of the partition depends on Arapaho's complex pitch accent system.