"when a multilingual person wants to speak, the languages they know can be active at the same time, even if only one gets used. These languages can interfere with each other, for example intruding into speech just when you don't expect them."
In Australia I often cause confusion when I switch to Hokkien/Mandarin or Malay midway. Sometimes I don't even realise I am doing this. In Malaysia most of us speak like this, inserting random words from languages all the time.
https://www.bbc.com/future/article/20220719-how-speaking-other-languages-changes-your-brain
@liztai I find switching can be challenging sometimes, I got a lot better at it but some situations that involve multiple languages can be tricky, for example watching an Italian film with a Thai native speaker, I almost always end up speaking Italian even though I intend to speak Thai and it's a real effort to get back into Thai mode.
@glotcha apparently there's also a diff between those who learned multiple languages at once (most Malaysians) and those who learned second languages much later. In the former, the languages are stored in the same area in the brain while the latter it's in different areas, hence the effort it takes for you to access them. For me I don't even realise I am doing it sometimes.
@liztai that's very interesting, thanks! I've had it a few times where you're speaking to a friend with whom you might use one of a few languages and then you can't quite work out which it was language you were just speaking :)