The following summarizes the sound system of the dialect of Tibetan spoken in
Lhasa, the most influential variety of the spoken language. The structure of a Lhasa Tibetan
syllable is relatively simple; no
consonant cluster is allowed and codas are only allowed with a single consonant. Vowels can be either short or long, and
long vowels may further be
nasalized.
Vowel harmony is observed in two syllable words as well as verbs with a
finite ending. Also,
tones are
contrastive in this language, where at least two tonemes are distinguished. Although the four-tone analysis is favored by linguists in China,
DeLancey (2003) suggests that the falling tone and the final or are in
contrastive distribution, describing Lhasa Tibetan syllables as either high or low.
Consonants • In the low tone, the unaspirated are voiced , whereas the aspirated stops and affricates lose some of their aspiration. Thus, in this context, the main distinction between and is voicing. The dialect of the upper social strata in Lhasa does not use voiced stops and affricates in the low tone. • The approximant /ɹ/ has four realizations [ɹ], [ʐ], [ɾ] and [r]. Some previous work postulates a voiceless approximant like [ɹ̥] (Dawson, 1980b; Sprigg, 1954; Tournadre & Dorje, 2003). In the current dataset, there is no clear evidence for this sound. It might be a variant of the sound /ʂ/ in certain varieties of Lhasa or Central Tibetan. • The consonants , , , , , and may appear in syllable-final positions. The Classical Tibetan final is still present, but its modern pronunciation is normally realized as a nasalisation of the preceding vowel, rather than as a discrete consonant (see above). However, is not pronounced in the final position of a word except in very formal speech. Also, syllable-final and are often not clearly pronounced but realized as a lengthening of the preceding vowel. The phonemic
glottal stop appears only at the end of words in the place of , , or , which were pronounced in Classical Tibetan but have since been elided. For instance, the word for
Tibet itself was
Bod in Classical Tibetan but is now pronounced in the Lhasa dialect.
Vowels The vowels of Lhasa Tibetan have been characterized and described in several different ways, and it continues to be a topic of ongoing research. Tournadre and Sangda Dorje describe eight vowels in the standard language: Three additional vowels are sometimes described as significantly distinct: or , which is normally an allophone of ; , which is normally an allophone of ; and (an unrounded, centralised, mid front vowel), which is normally an allophone of . These sounds normally occur in closed syllables; because Tibetan does not allow
geminated consonants, there are cases in which one syllable ends with the same sound as the one following it. The result is that the first is pronounced as an open syllable but retains the vowel typical of a closed syllable. For instance,
zhabs (foot) is pronounced and
pad (borrowing from Sanskrit
padma,
lotus) is pronounced , but the compound word,
zhabs pad (lotus-foot, government minister) is pronounced . This process can result in
minimal pairs involving sounds that are otherwise allophones. Sources vary on whether the phone (resulting from in a closed syllable) and the phone (resulting from through the
i-mutation) are distinct or basically identical. Phonemic vowel length exists in Lhasa Tibetan but in a restricted set of circumstances. Assimilation of Classical Tibetan's suffixes, normally '
i (འི་), at the end of a word produces a long vowel in Lhasa Tibetan; the feature is sometimes omitted in phonetic transcriptions. In normal spoken pronunciation, a lengthening of the vowel is also frequently substituted for the sounds and when they occur at the end of a syllable. The vowels , , , , and each have nasalized forms: , , , , and , respectively. These historically result from , , , , , and are reflected in the written language. The vowel quality of , and has shifted, since historical , along with all other coronal final consonants, caused a form of
umlaut in the Ü/Dbus branch of
Central Tibetan. In some unusual cases, the vowels , , and may also be nasalised.
Tones The Lhasa dialect is usually described as having two tones: high and low. However, in monosyllabic words, each tone can occur with two distinct contours. The high tone can be pronounced with either a flat or a falling contour, and the low tone can be pronounced with either a flat or rising-falling contour, the latter being a tone that rises to a medium level before falling again. It is normally safe to distinguish only between the two tones because there are very few
minimal pairs that differ only because of contour. The difference occurs only in certain words ending in the sounds [m] or [ŋ]; for instance, the word
kham (, "piece") is pronounced with a high flat tone, whereas the word
Khams (, "the
Kham region") is pronounced with a high falling tone. In polysyllabic words, tone mainly distinguishes meaning in the first syllable. This means that from the point of view of phonological
typology, Tibetan could more accurately be described as a
pitch-accent language than a true
tone language, in the latter of which all syllables in a word can carry their own tone. == Verbal system ==