Any Tibetan language romanization scheme is faced with a dilemma: should it seek to accurately reproduce the sounds of spoken Tibetan, or the spelling of written Tibetan? These differ widely as Tibetan orthography became fixed in the 11th century, while pronunciation continued to evolve. Previous transcription schemes sought to split the difference with the result that they achieved neither goal perfectly. Wylie transliteration was designed to precisely transcribe written Tibetan script, hence its acceptance in academic and historical studies. It is not intended to help in the correct pronouncing of a Tibetan word.
|ཀ ka [ká]||ཁ kha [kʰá]||ག ga [ɡà/kʰà]||ང nga [ŋà]|
|ཅ ca [tɕá]||ཆ cha [tɕʰá]||ཇ ja [dʑà/tɕʰà]||ཉ nya [ɲà]|
|ཏ ta [tá]||ཐ tha [tʰá]||ད da [dà/tʰà]||ན na [nà]|
|པ pa [pá]||ཕ pha [pʰá]||བ ba [bà/pʰà]||མ ma [mà]|
|ཙ tsa [tsá]||ཚ tsha [tsʰá]||ཛ dza [dzà/tsʰà]||ཝ wa [wà]|
|ཞ zha [ʑà/ɕà]||ཟ za [zà/sà]||འ 'a [ɦà/ʔà]||ཡ ya [jà]|
|ར ra [rà]||ལ la [là]||ཤ sha [ɕá]||ས sa [sá]|
|ཧ ha [há]||ཨ a [ʔá]|
The final letter of the alphabet, the null consonant ཨ, is not transliterated - its presence is unambiguously indicated by a vowel-initial syllable.
In Tibetan script, consonant clusters within a syllable may be represented either through the use of prefixed or suffixed letters, or by letters superfixed or subfixed to the root letter (forming a "stack"). The Wylie system does not normally distinguish these as in practice no ambiguity is possible under the rules of Tibetan spelling. The exception is the sequence gy-, which may be written either with a prefix g or a subfix y. In the Wylie system these are distinguished by inserting a period, . between a prefix g and initial y. E.g. གྱང "wall" is gyang, while གཡང་ "chasm" is g.yang.
The four vowel marks (here applied to the silent letter ཨ ) are transliterated:
|ཨི i||ཨུ u||ཨེ e||ཨོ o|
Wylie's original scheme is not capable of transliterating all Tibetan-script texts. In particular, it has no correspondences for most Tibetan punctuation symbols, and lacks the ability to represent non-Tibetan words written in Tibetan script. (Sanskrit and phonetic Chinese are the most common cases.) Accordingly, various scholars adopted ad hoc and incomplete conventions as needed.
The Tibetan and Himalayan Digital Library at the University of Virginia developed a standard, THDL Extended Wylie Tibetan System or EWTS, that addresses these lacks systematically. It uses capital letters and Latin punctuation to represent the missing characters. Several software systems, including TISE, now use this standard to allow one to type unrestricted Tibetan script (including the full Unicode Tibetan character set) on a Latin keyboard.