polite in English

last week after Victoria watched Enzo he came home and said "thank you" along with the sign. I've been doing the sign with him but was surprised to hear the "thank you". When I came back from my trip he was saying "please" along with the sign. He also says "sorry". I wanted to take the credit for his good manners so bad but how could I when I don't speak English to him? Today when I picked him up from her house she was saying "thank you Enzo" and doing the sign back to him and again he did "thank you" back to her. Either saying Obrigada, Por Favor, and Desculpa is too hard or we're just not doing a really good job. Avi says Agua, does that count as a trade?