Now, Charlotte's Swedish is pretty fluent, and we have no proof that she is actually English as she has never shown voice clips, whereas Angelica is definitely Swedish, but only these two comments from both sides could prove anything:
Angeliiicaaa__: "Vi är tekoppar :V"
N1mka4eva: "Vi är bättre än er. Två av det bästa som finns, kan det blir bättre? Nej. We're lovely people :D"