I’m glad I’m not the only one to notice how enthusiastically she performs her job.
She may be enthusiastic, but what I believe you are referencing is not necessarily the product of ‘enthusiasm’ - it’s the way deaf people communicate.
ASL isn’t a real language, and powerful facial expressions come naturally with it, to clarify and emphasize meaning. Even deaf people who don’t use sign language seem to have very expressive faces and gestures - it helps them to be understood, as with many their speech isn’t always clear. Hearing people who communicate with the deaf do the same thing, so that they are understood as well.
This isn’t often the same with people who went deaf late in life, but generally true of those who were deaf from birth, or who are trained in communicating with the deaf.
I know, right? She deserves an Oscar for her performance.