It's always preferable to translate directly from the original language, rather than translating from another translation as this can lead to an accumulation of inaccuracies. The quote you are familiar with is a Spanish translation of Nezahualcoyotl's poem, which he wrote in Nahuatl (the Spanish language only arrived in Mexico after Nezahualcoyotl's lifetime). The original version is: Nehhuātl nictlazohtla in centzontōtōtl īcuīc, nehhuātl nictlazohtla in chālchihuitl ītlapaliz īhuān in nepapan ahhuiyāc xōchitl; zan oc cencah nocnīuhtzin in tlācatl nehhuātl nictlazohtla. I'm no poet, so here's a literal translation into English: I love the song of the mockingbird, I love the colour of jade, And the various fragrant flowers; But especially my dear friend Man I love The line "pájaro de cuatrocientas voces" is due to the fact that the word the poet uses for "mockingbird" is "centzontōtōtl", which is made up of "centzontli" = "four-hundred" and "tōtōtl" = "bird": the bird of four-hundred [voices]. "Enervante" seems to have come from the Spanish translator's imagination.

"I love the singing mockingbird, the bird of four thousand voices. I love the jade-green color and the fading fragrance of flowers; but even more I love my brother, Man." From what I have seen about Nezahualcoyotl, this version based on your English seems to capture the spirit of the poem. The word "enervate" means "to diminish" or "weaken" so "fading" seems to fit. It seems the poet uses "perfume" in several poems so you may also choose to use "perfume" in place of "fragrance" but using "fading fragrance" maintains the poetic alliteration that seems important to this style of poetry. I have suggested the ending "my brother, Man" to emphasize the poet's concept of "Man" as "all humanity" and the connection of the individual to all people (and things, including the spirit world). This also appears to be an important theme throughout the poet's work. I am interested to hear what you think.

Hundred*