"The whole world is sighing and explaining the language, and I don't know who it is for." What does this sentence mean?

"The whole world is sighing and explaining the language, but I don't know who it is for." This sentence means: "Everyone is sighing and praising the beauty of understanding, but I don't know who it is for."

Emperor Xuanzong of the Tang Dynasty compared Yang Guifei to a famous talking flower here, and later used "Xie Hua, Xie Yu turned to the country" as a metaphor for beauty, or referred to beauty as lovely.

Source: According to the "Kaiyuan Tianbao Legacy", "The emperor (Tang) and his concubine (Yang Guifei) * * * were enjoying the lotus in Chiba, pointing to the concubine and saying,' Why are you so eloquent?' "This is the origin of the word' Jieyu Flower'.