Mongolian script multigraphs
This article describes two- and three-letter combinations (so-called digraphs and trigraphs) used for the Mongolian language when written in the Mongolian script. Vowel and consonant combinations 
The intervocalic letters /, and  has in some combinations come to help form long vowels, namely: Long  with: , , . Long  with: , , . Long  with: . Long  with: , , . Long  with: , , . Long  with: , . Long  with: , , . Sometimes intervocalic  and  is silent: as in   ( ) 'robe, garment' or   ( ) 'human, person; man'. Vowel combinations 

 The doubled vowels , , and  mark these out as long. Doubled  is instead both used in a few words to mark the vowel as short, and to distinguish it from . Most of the 's of these diphthongs derive from an earlier , but is no longer recognized as such. The  origin can for instance be seen in the two long teeth of   'good'. These has become a pair of short and long teeth  in recent manuscripts. The diphthongs only appears with the single form of , as in  '' 'sea', at the end of words. Notes

References 

Articles containing Mongolian script text
Mongolic letters
Mongolian language