The story
From Mandarin 國語／国语 (guóyǔ, literally “nation-language” or “country-language”).
Etymology from Wiktionary, CC BY-SA 4.0.
Guoyu
Guo·yuToday it means: The standardized spoken Chinese language, also referred to as Standard Mandarin. The term remains in common use in the Republic of China (Taiwan) and colloquially in Hong Kong (along with Putonghua). In mainland China, Guoyu or Taiwan Guoyu is used to refer to Taiwanese Mandarin (standard), as opposed to mainland standard Mandarin. Full definition →