The winger joined Bayern in January from Granada for 4.5m after initially signing a pre-contract to join in June.
Tuchel said: "He doesn't understand the language. Both German and English are difficult for him, and that's basic. We brought forward the signing to save time with this. I knew it would be a very big step for him.
Advertisement
Advertisement
"We see his quality, but right now he cannot fully integrate because of the language.
"That is why we are going to be patient with him."