>>>On the othest hand, there are those who can drop back and forth between two languages several times during a sentence. The phenomenon is known as code-switching.

That's exactly what happens at our family suppers where we'll switch from French to English and back again, depending upon who we're facing when discussing something.

My Dad and all of my siblings are perfectly bilingual speaking both English and French fluently. My Mom is more at ease speaking French but understand English very well. One sis-in-law is unilingually French, while the other sis-in-law is unilingually English, my bro-in-law is French with a smattering of English knowledge.

Any new person to the table can find our interactions quite confusing as a sentence can start in one language, switch to another when we face a different person, and finish off in the first; all without skipping a beat.