The traditional or classical
Mongolian alphabet, sometimes called
Hudum 'traditional' in
Oirat in contrast to the
Clear script (
Todo 'exact'), is the original form of the
Mongolian script used to write the
Mongolian language. It does not distinguish several vowels (
o/
u,
ö/
ü, final
a/
e) and consonants (
t/
d,
k/
g, sometimes
ž/
y) that were not required for
Uyghur, which was the source of the Mongol (or Uyghur-Mongol) script. The result is somewhat comparable to the situation of
English, which must represent ten or more vowels with only five letters and uses the
digraph th for two distinct sounds. Ambiguity is sometimes prevented by context, as the requirements of vowel harmony and syllable sequence usually indicate the correct sound. Moreover, as there are few words with an exactly identical spelling, actual ambiguities are rare for a reader who knows the orthography.