considering language switching, I can provide you with some theory.
Children growing up with two or more languages (either in bilingual way or in adding a second language after being three years old) learn in which situations a language will be appropriate, so they seldomly switch uninentionally. The reaction to the perfect pronounced name is a regular one, since the brain automatically expexted a native speaker there. Uninentional language switching mostly happens if the speaker knows that all people around him share the same vocab for fitting situation.
Example: You have grown up with english and french. Let's say you grew up bilingual and have a vocab considering "family" in both languages, but "school" is reserved for english. If you do not have friends speaking french there with you, you won't slip into french there without little exceptions. If you have friends there from a french context you might slip into french with them if no one else is around and depending on the topic. Many bilingual grownups have a language they feel saver with if it comes to emotions. They can equally talk about them in both languages intentionally. If they meet someone of the language preferred by the brain in a context that would not require you to keep track which language to use, you will speak a vivid mix of french and english and talk about emotional topics mostly in french (if that is the preferred language) since you know your above can switsch fluently as well.
I know it from german-turkish and german-kurdish pupils mostly. Those never react in their native language to me except if it comes to swears (and that only if they lose controll). If you listen to them on the yard while none of their only german friends is around you will hear school vocab in german only mixed with a lot of stuff in the other languages. School vocab is seldomly referred to in their main tongue at home.
If you not only have gained knowledge about syntax and grammar but as well about what your partner in talks or surroundings are capable of understanding and which language is expected from you, you can intentionally switsch. Bi- and Multilingual grown-ups have advantages here. Those who added other languages later to their mother tongue can gain that fluency as well.
Haiz describes a situation where one of the main languages (norwegian) get's mixed unintentionally since they talk very often in english context. Main language gets pushed aside and mixed. According to literature this mostly happens if one is not able to pay attention to social surroudings (for example if one's mind is busy with planning, trouble...), or knows some words for a situation fitting in one language but not in the other and thus is in unconcious need of mixing.
Eh okay, lecture is over. I am able to switch from german to english and back but still am in need of a dictionary at times. If I expect someone to know bits of german or a language sharing some words, I try to sneak in german words in hope of the person being able to make a guess (I do that while trying to talk norwegian from time to time).
Heh, yeah, this all matches my experience. Austrian (Croatian minority) dad, Finnish (Finnish-Finnish, but from mixed, near the coast area), grew up in Sweden. They started out using their respective languages with me, then decided that one should speak Swedish (my mother did), and in Sweden you get some schooling in one of your parents' native language, so I learned Finnish that way.
As I learned both the Croatian, and the Finnish from non-peers (?), I'm terrible at cursing in those languages.
Anyway, I've always found it easy to keep the languages apart.
What I do need to improve is vocab, both when it comes to Croatian and Finnish. I tend to do like several others have written they do: use appropriate language (e.g. Croatian with my dad), then replace missing words with secondary language (e.g. German), and if that is missing, use Swedish. Hehe.