Some Western scholars propose that the relatively well researched Ordos variety is an independent language due to its conservative syllable structure and phoneme inventory. While the placement of a variety like Alasha, which is under the cultural influence of Inner Mongolia but historically tied to Oirat, and of other border varieties like Darkhad would very likely remain problematic in any classification, the central problem remains the question of how to classify Chakhar, Khalkha, and Khorchin in relation to each other and in relation to Buryat and Oirat. The split of into before *i and before all other reconstructed vowels, which is found in Mongolia but not in Inner Mongolia, is often cited as a fundamental distinction, for example Proto-Mongolic ', Khalkha , Chakhar 'year' versus Proto-Mongolic ', Khalkha , Chakhar 'few'. On the other hand, the split between the past tense verbal suffixes -' in the Central varieties vs. -' in the Eastern varieties is usually seen as a merely stochastic difference.