。
She read the poem aloud.
Literal
She [topic-は] that poem [object-を] voice [out-に] putting read.
声に出して ('aloud,' lit. 'putting [it] out as voice') is the standard phrase for vocalizing — 声に出す literally 'put out as voice,' with the て-form linking it as a manner adverbial to the next verb. The structure: 声 + に + 出す (out) + て + [verb]. Reading poetry aloud has a long tradition in Japanese — 朗読 ('reading aloud') is part of school education, and 詠む ('to compose/recite') is the historical verb for poetry, distinct from 読む ('to read').