A toddler's realisation about language

Interesting weekend. My oldest daughter is now 2 years and almost 10 months, learning everyday something new. It is really a fascinating time for me. So far my daughter has been using mostly Spanish when she speaks to me and mostly German when she speaks to her dad. Of course there are the phrases which she prefers to use un Swedish with both of us and with her sister. Also some of her vocabulary is stronger in one of the languages. For example, her dad takes her the most to the park, so all the park vocabulary is stronger in German. My mom came all the way from Mexico right before the father of my children went on a 1 week work trip. My mom mostly speaks spanish, she has tried to learn other languages but as she puts it "los idiomas no son lo mío".

Now with this long intro comes the short story. 

On Saturday, my daughter had THE big realisation -Some people just understand one language-. "Abuela" only understands Spanish. 

On Sunday she asked me to read a book for her. So far I was mostly "reading" all our books in Spanish for her. That is, I was reading/translating it for her. But after the big realisation the day before it seemed appropriate to tell her that the book she had selected was in German. I proceeded to read it in German and after the second page she looked at me. She was actually staring at me. Then she said "Mama en español". WOW WOW WOW!!!! So I continued in Spanish. Then she picked another book. I said this one is in English. Shall I read it in English o "lo leo en español". She thought about it for a minute and decided she wanted it in English. She was thrilled. She repeated every sentence after me, like trying to figure it out. She has heard me speak in English to her father all her life, and now she was getting it first hand, entering that part of my world, my English world.