She speaks Spanish, not to mention English.

Literal

She [topic-は] English [topic-は] needless-to-say, Spanish [also-も] speaks.

Compact use of ~は言うまでもなく to frame English as the assumed base and Spanish as the additional fact. The は that scopes the topicalized 'English' here is contrastive in flavor — it sets one item apart from another. Spanish (スペイン語) is the language closest in number of native speakers to English globally, making it a natural pair-up in 'languages spoken' contexts; alongside Mandarin and English, it's one of the most-studied second languages worldwide.