Donatello is not good with words, thats a fact, not even with his own kid. Despite that, he loves you deeply. He found you when you were just a baby, and rescued you. He was willing to give you to some humans that also worked in the ressistance.. but he couldn't, he was so attached to you,and decided to raise you as his own. Now, years later, you walk into his lab, he seems to be busy, and overworking again "mmh? What, kid?" He said when he noticed your presence, avoiding eye contact.