What is the similarity and difference in the language that you speak in comparison to the language your parents speak?
Answers
This is a common misconception: The first language you spoke as a child is your "first language", but you can completely forget it over time (or pretty much all of it). My first language was German (actually "Schwäbisch" dialect), because my grandma spoke that and she lived with us after my father died so my mother could work. So I grew up speaking German with my sister. We spoke English, too, and I remember saying to her: "Hey, let's speak English" and finding talking to her in English vastly amusing. But it stuck. My mum married again (an English-speaker), our Grandmother moved out, and we used German only on the occasional holiday. So it gradually dried up. I went to school and spoke Italian there, so I grew up Italian / English bilingual. German, my first language, faded almost entirely, and many years later I had to re-learn German at school, and I struggled with the grammar (and still do today).
Your "primary" language is your dominant language at any given moment in time, but of course that can change. 10 years ago, my primary language would have been English - no hesitation. Now it's English, but also German. And French, almost. And Italian. But the exact weighting of each language shifts as I use a language more or less.
Don't worry about it. Some people have this strange idea that your first language is somehow magical and is tattooed into your brain forever. It isn't. You may even not have any special bond to that language later in life. Don't sweat it.
Oh yeah - some people ask we (usually in an exasperated voice): "Well, what language do you count in?" That depends what language I'm speaking at the time. I use that. Or "Well, dammit, what language do you dream in?" That's no good either: I dream in images of visual sequences and sometimes dream that I can speak Swedish or Russian (which I certainly can't when I'm awake...).