Hmm I'm not as familiar with Sign languages, especially the one(s?) used in Germany, but I'm gonna say she doesn't. I bet she's tried out of curiosity, but I also think she'd be the kind of person that falls into the trap of thinking signs are just gestures to replace words. Spacial and facial grammar would be totally lost on her.
And while I don't think she personally holds this prejudice, it's important to note that that teaching method named after her I mentioned was based on the belief that the purpose of learning a new language is to be able to read its literature. Given that she's a canon bookworm I imagine even if she doesn't believe that literally, the ability to have access to entirely new bodies of literature probably motivates her like crazy. Though written versions of Sign languages have been created there's not much of a body of literature yet, and without motivation even someone with the best ability is gonna have a hard time.
Re: Percentage of population able to hold a conversation in English in the EU by country.
And while I don't think she personally holds this prejudice, it's important to note that that teaching method named after her I mentioned was based on the belief that the purpose of learning a new language is to be able to read its literature. Given that she's a canon bookworm I imagine even if she doesn't believe that literally, the ability to have access to entirely new bodies of literature probably motivates her like crazy. Though written versions of Sign languages have been created there's not much of a body of literature yet, and without motivation even someone with the best ability is gonna have a hard time.