Scholars in the circle of Mongolian language studies have worked on non?initial short vowels in spoken Mongolian naming them as “reduced vowel” or “super?short vowel” or “dependent vowel”. However, the most of the scholars give attention to them from the angle of phonology, and describe them in traditional method of audition. Up to today, the timbre and its multiformity of the non?initial short vowels, as well as the existence of them have been a pendency of phonetic descriptions and phonemic interpretations. In this article, the present author reaches the following conclusions by the analyzing method of the acoustic phonetics:
a)In acoustic feature, the short vowels in the second syllable are resonant and intensive; b)in physiological feature, they show a tendency of “centralization”; c)in auditory feature, they are nondistinctive vowels. Therefore, the “reduction of tone” and “decrease of distinction” are important features of the short vowels in the second syllable of spoken Mongolian.