Having children is a wonderful way to learn a new language. Above all when they are learning to speak or to read. My son is now two-years-and-a-half. An age at which he is learning constantly. He experiments with the environment, with his own body (running, jumping, climbing) and wants to communicate with us. In a bilingual family, this means that he is learning two languages, German thanks to his father and Spanish thanks to me (and some English thanks to the TV).
However, pretty early on I was determined that whatever words I could mutter in German, I would teach him them first. The same with basic concepts as big/small, colours, numbers, food, etc. This means that I must first learn these words and expressions and then reproduce them. This also means that I read to him more books in German than in Spanish. Children books are a great tool to learn a new language. For German, my favourites are the series Wieso? Weshalb? Warum? by Ravensburger. We have quite a collection now. They are truly educative and entertaining for adults and children alike.
Apart for reading, we listen to music mainly via YouTube. You can find channels like Sing mit mir – Kinderlieder that have captions to follow along. Still, the biggest hit at hour home remains Die Eule mit der Beule.
In resume learning along with him, reading to him and singing have been a big help. But the most important thing is that I always talk to him in my broken German first and switch to Spanish when I don’t find the words. Then, back to German. Practising German with him, although my vocabulary is limited, has greatly improved my confidence. And confidence in oneself is all when speaking a foreign language to natives.