Complex sentence: The contrast between the two accents in vowels and complex diphthongs is disappearing, because the opposition between the two accents is not present in all the dialects, the base dialects of a standard language (western Aukštaitian) cover a smaller area.
Split into simpler sentences: The contrast between the two accents in vowels and complex diphthongs is disappearing, because the opposition between the two accents is not present in all the dialects. The base dialects of a standard language (western Aukštaitian) cover a smaller area.