English is my first language, though Spanish is not far behind, since I've spoken it since approximately age 4 and can't remember a time when I didn't know it. So I was raised in two languages thanks to my grandmother being from Mexico and making sure that her grandchildren grew up speaking it. My parents, however, were both monolingual English speakers. In practice, this meant having to translate for my mother from a very young age (including some places where it was super illegal, like the doctor's office she worked at; nobody cared about this aspect back then, of course).
Since about age 19 I set about learning Russian, which I ended up studying for 6 years but haven't really spoken since then). I would say it is passively still in there, but I need to be back in an environment where I would need to depend on it to 'reactivate' it. Most recently (by which I mean in college, almost 20 years ago) I took a year of Arabic classes, which in the U.S. basically just means enough to read and write, but not really enough for much vocabulary-building. That would come later via the Coptic Orthodox Church from 2009 to present, which has been very helpful in some ways (Egyptian Arabic is the most widely-understood Arabic dialect, so it's a good one to have a lot of exposure to), and somewhat unhelpful in others (you can guess how weird it is to essentially speak and understand 'Church Arabic' -- i.e., to have the liturgy and various 'churchy' things down pat, but to still struggle with other topics in the language.
I'm not sure what aspect you're referring to in the opening post when you ask about "that aspect", OP, but I do find that having knowledge of multiple languages is helpful. Even more so, I'd bet, when they are genetically unrelated to each other (as Arabic is to the Indo-European languages) or very distant relatives (as I would say Spanish and Russian are; clearly related insofar as they are both Indo-European, but there's really not a lot of crossover), since it is in some sense 'easier' (for me, anyway) to look at them from a macro level to see how they all work, and make connections between them in ways that help me learn more about and in each one. (Though that could also be the training in linguistics, since I have a master's degree in the subject.)