¯) low (symbol: grave accent `) The tonal system is however marginal. Trager describes the tones as being distinguished by pitch differences. The mid tone is by the most commonly occurring tone; high tone is limited to a few stems and suffixes; the low tone is relatively common in stem syllables. The high tone is described as "higher and sharper" than the mid tone while the low tone is "distinctly lower and drawling". Many words are distinguished solely by tonal differences as in the following minimal pairs which demonstrate the contrast between the mid tone and the low tone in stressed syllables: {| cellspacing="4" | || ('pass by') || || || || ('one') |- | || ('suck') || || || || ('it is real') |} There is no tonal contrast in unstressed syllables, which have only phonetic mid tones. Thus, the word ('plum') has the unstressed syllables and which have phonetic mid tones resulting in a phonetic form of . initially found the stress level to be predictable in syllables with high and low tones; however, finds this to be in error with the addition of newly collected data and a different theoretical outlook. (See stress section above.) In his final historical notes, suggests that in proto-Taos (or in proto-Tiwa) there may originally have been only a stress system and a contrast of vowel length which later developed into the present tonal-stress system and lost the vowel length contrasts. Syllables and phonotactics The simplest syllable in Taos consists of a single consonant in the onset (i.e. beginning consonant) followed by a single vowel nucleus, i.e. a CV syllable. An onset and nucleus are obligatory in every syllable. Complex onsets consisting of a two-consonant cluster (CC) are found only in loanwords borrowed from New Mexican Spanish. The nucleus can have optionally two vowels in vowel clusters (V or VV). The syllable coda (i.e. the final consonants) is optional and can consist of up to two consonants (C or CC). In other words, the following are possible syllable types in Taos: CV, CVV, CVC, CVVC, CVCC (and in loanwords also: CCV, CCVV, CCVC, CCVVC, CCVCC, CCVVCC). This can be succinctly represented in the following (where optional segments are enclosed in parentheses): C1 (C2)V1(V2)(C3)(C4<) + Tone Additionally, every syllable has a tone associated with it. The number of possible syllables occurring in Taos is greatly limited by a number of phonotactic constraints. A