I have a whole new level of respect for Daniel Day-Lewis. Having only seen his more recent works (last 20-ish years) I was missing out on this one and I'm so happy to have filled that blank spot. He's incredible, he displays the progression of learning to such a specific degree that it's hard to imagine training yourself to accomplish that as a fully physically capable person.
The same level of praise can be given to Brenda Fricker as Mrs. Brown. She embodies the image of a loving mother and devoted wife, wholly capable of supporting and defending her family while nurturing them in love.