@Gabrielle72,
Gabrielle:
If you listen very carefully to President Obama and his wife, when they're speaking, you'll think they're making mistakes in English. However, if you ever travel and live in Chicago, you'll find that what you think are mistakes in English are considered by most folks living there to be normal.
Remember both Mr. and Mrs Obama graduated from Harvard Law School and President Obama was at one time an adjunct professor at the U of Chicago Law School.
One very common mispronanciation the Obamas make ( as do I, also being from Chicago ) is saying ta for to. "I'm going ta the White House for a visit".
Remember, that correct and acceptable American English varies considerably across the USA
We Americans may not speak the kind of English you learned in Europe, but we're still kind and gentle folks, who do try hard.