Though it is probably wrong to speak either of wildness or a "joke" in relation to "Never Again Would Birds' Song. . .," still the "eloquence so soft" with which Frost unrolls this quietest and most discreet of his sonnets, has about it the air of a tour de force. Like his heroine Eve, he has added "an oversound" to the world of created sounds--bird calls, love calls, sonnets, in which he lives. The sonnet's cunning phrasing, with its artfully polite phrases--"Admittedly," "Moreover," "Be that as may be," all at the beginning of lines--suggests the impressive blend of delicacy and firmness with which the case is made for Eve's persistence in song. . . .
From Robert Frost: A Literary Life Reconsidered. Copyright © 1984 by William Pritchard.