。
She kept on talking.
Literal
She [topic-は] talk [continued-つづけた].
A simple compound verb showing ~続ける ('keep doing'). しゃべる has a noticeably more casual flavor than 話す ('speak') — closer to 'to chatter' or 'to gab,' often with a hint of someone going on more than necessary. The hiragana-only writing しゃべりつづけた reflects the casualness; you'll also see it written 喋り続けた with kanji. Together, the casual verb choice and the continuative auxiliary paint a vivid picture of someone yakking on without pause.