Faced with the formidable task of learning a new language, she felt initially overwhelmed.

formidable 是由词根 formid（恐惧）和后缀 -able（能够...的）组成的形容词，字面意思是"能引起恐惧的"，引申为"令人敬畏的、艰巨的"。这个词强调任务或挑战的难度大到令人望而生畏的程度。