The author estimates the phonetic values for the onset of the Middle Mongolian syllables represented by ?? in The Secret History of the Mongols through examination of the use of the character.
The examples listed in (1) and (2) lead one to the conclusion that ?? represents Middle Mongolian en. However, the non-use of ?? in the examples in (3) gives evidence in favor of the opposite conclusion. More-over, the words in (4) and (5) show that ?? is used to transcribe Middle Mongolian yen.
Having accepted Hattori's (1987) hypothesis, the author explains this situation by sketching out the following phonetic history of Mongolian concerning the syllable having e as a nucleus:Consonants in a weak po-sition, i. e. a position between a short vowel and a long vowel, were almost disappearing at the time of the Chinese transcription. This is why ?? is used in (1) and (2) for the syllable with no coda. But, they had not yet completely weakened, and sometimes had a value of [_??_], which was pro-nounced with a narrow constriction in the vocal tract between high or mid vowels or combinations of both, and therefore sounded like a non-syllabic vocoid. In addition, there was no suitable character for Mongolian en in the Chinese dialect of that period on which the transcription was based. Consequently, ?? is used in (1) and (2) for the syllable containing n as a coda. When the syllable was preceded by a high vowel, an intrusive consonant appeared in some words as an onset of the syllable. This explains the use of ?? and ?? in (4) and (5).
The existence of the non-syllabic vocoids as an onset of the syllable is supported by the examples from the texts of Arabic transcriptions shown in (9).
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