That's all irrelevant. It's always been the case at Inter that everyone speaks Italian.
And it's always been the case that some people didn't speak it very well.
Lautaro didn't speak it well when he arrived as close as it sounds to Spanish, it's not grammatically as similar (French is closer for example in that aspect). But Lautaro had Icardi, Vecino, Balde, Valero, Miranda and possibly Vrsaljko who also spoke Spanish so he didn't really need to learn Italian very quickly in order to adapt.
Eriksen speaks English and he's unlucky that guys like Young and Lukaku are the complete opposites of him in terms of character. The level of English of our Italian players is questionable so you're left with De Vrij, Nainggolan, Sanchez and perhaps Brozovic, Perisic and Skriniar that can communicate in English to a degree. His only real 'fit' in terms of personality is De Vrij, but De Vrij speaks fluent Italian and doesn't really "need" Eriksen as much as he needs him. But perhaps Eriksen being able to communicate with De Vrij in Dutch as well can help somehow. It always felt like a good combination but I'm not sure if that Ajax-Feyenoord rivalry follows in the locker room