Was it Robert Frost who said that a translation should "talk a poem into English?" I thought that was the quote; however, what Frost said was this: seeing Stanley Burnshaw's edition of The Poem Itself, Frost remarked, "Instead of translating a foreign poem, you discuss it into English." This remarkable book does not offer translations of the French, German, Italian, Spanish and Portuguese poems contained within, rather, in the notes following the text, there is a line- for-line translation which accompanies discussion of the poem.
Frost had said about poetry that it was what "got lost in translation." I am assuming without seeing this famous quote in context that he meant what was lost in paraphrase of "English to English" or "translation" from a foreign language into English. Leaving aside for now this assumption, I would like to quote an admonition for those who translate verse from another language into English:
The assertion that it is the translator's duty first and foremost to write a poem needs to be accompanied by a reminder that every poem (that is a poem) is a new poem. Every poem is an experiment. An urgent original, one that, in Osip Mandelstam's phrase, disturbs meanings, must not be turned into something the opposite of urgent, something faded, that does not press to be uttered. Which is what most often happens. Poems that once were disturbers of meanings are turned into faded imitations of themselves, where all meanings lie deathly quiet. Any techinque that prevents the Englishing of a poem in this way is fit for use. Any that distracts from the translator's prime duty is to be eschewed (Peter Whigham, " Introduction," p. 39, Epigrams of Martial: Englished by Divers Hands, J.P. Sullivan and Peter Whigham, eds., University of California Press, 1987).
In his 'new poem,' FitzGerald's genius lies in giving voice to what in Khayyam "presses to be uttered."