in an underlying consonant phoneme. Nouns apparently ending in a vowel actually have a glottal stop or a glottal fricative as the final consonant. Such consonants become realized when suffixes are attached. The distinction between phonemes and is neutralized at the end of words. Free variation There is free variation of some consonants in Choctaw with some speakers: /ɬ/, the voiceless lateral fricative, is pronounced as a voiceless dental fricative [θ]: →. The voiceless labiodental fricative /f/ is pronounced as a voiceless bilabial fricative [ɸ]: →. Phonological processes of consonants In Choctaw , the voiceless velar plosive, is often pronounced as , a voiced velar fricative, between vowels. →/V_V imofi-aki-lih→imofiy-əɣə̃:-lih The voiceless glottal fricative is often pronounced like a voiceless palatal fricative when it precedes the voiceless palato-alveolar affricate . →/_ katihchish→katiçtʃiʃ Vowels Lax vowels occur more often in closed syllables. In traditional orthography, ʋ usually indicates and u usually indicates . Exceptions include pokoli (traditional) for , imalakusi for . The traditional orthography doesn't distinguish lax and tense front vowels; instead it indicates with e. Nasal vowels are intrinsically long. Pitch In Choctaw, very few words are distinguished only by pitch accent. Nouns in Choctaw have pitch realization at the penultimate syllable or the ultimate syllable. Verbs in Choctaw will have pitch realization at morphemes indicating tense, but sometimes, pitch directly precedes the tense morpheme. Syllable structure As is in the chart above, there are three syllable structure types in Choctaw: light, heavy, and super heavy. Possible syllables in Choctaw must contain at least one vowel of any quality. Syllables cannot end with a consonant clusters CC. However, there is an exception with the structure *(C)VCC if a word in Choctaw ends with the suffix /-t/. Syllables do not begin with consonant clusters CC, but there is an exception in an initial /i-/ deletion, which results in a syllable *CCV . Rhythmic lengthening Rhythmic lengthening is the process of lengthening the vowel duration of an even-numbered CV syllable in Choctaw. However, vowels at the end of words are not permitted to undergo that process. Also, if an even-numbered syllable is a verbal prefixes class I or III, the affix's vowel may not undergo lengthening, and the same holds true for noun prefixes class III as well. CV-CV-CVC→CV-CV:-CVC salahatok→sala:hatok Smallest possible word The smallest possible word in Choctaw must contain either two short vowels or one long vowel. a:t /a-/