private bool RegionalDialectsFilter(LanguageInfo li) { if (IncludeRegionalDialects) { return(true); } // always include Chinese languages with region codes if (li.LanguageTag.IsOneOf("zh-CN", "zh-TW")) { return(true); } return(string.IsNullOrEmpty(IetfLanguageTag.GetRegionPart(li.LanguageTag))); }