In Slovene, sound shapes of Japanese and Chinese words undergoing the process of assimilation may be quite different from their origins, which in the end should not come as a surprise as it is so in many other languages. However, the fact that there are many cases with two slightly different Slovene pronunciations of the same Japanese or Chinese word, of which one is closer to the original sound shape than the other, calls for a more comprehensive investigation on the factors that contributed to such a result. This research pays attention to vowel sequences in Japanese and Chinese, and how they appear in Slovene as the so called visiting lexica. Though the two languages carry out vowel sequences in different ways, similarities can be found in the way Slovene detects and resolves their vowel hiatuses. Authors stress the importance of metrical aspects of the original sound shapes, which Latin script includes inconsistently or does not express at all. Phonological approach to vowel sequences solution to vowel hiatus and offers systematic guidelines on pronunciation of the Latin script. Besides, it may further bring some new insights into possible solution on conjugation and declination forms of Japanese and Chinese loanwords in Slovene.