Having the ability to learn, comprehend and speak multiple languages fluently, is a marker of intelligence. I mean, a basic definition of intelligence is often the ability to learn/acquire knowledge and apply it efficiently. Speaking multiple languages fluently is a reflection of said concept. I don't even know why this is debatable. At no point did I say he is Einstein, just that he is intelligent. Again, intelligence isn't a straight line.
Not for me and I'm an Afro Latino British diaspora kid from South London myself, who has lived in 3 continent and speaks 3 languages. I do not have a limited circumference of friends or anecdotes, and there's no way in hell speaking 5 or 6 languages is "fairly normal" anywhere I have been.
Being intelligent and being an idiot aren't mutually exclusive. And no, that's not what I am essentially saying. What I'm essentially saying is that Lukaku is intelligent and that his proficiency with languages is a marker of intelligence.
And where did I say it makes one more intelligent than others? And you're wrong. It is indeed a marker of intelligence. However, intelligence isn't a straight line and being proficient in multiple languages doesn't mean it will translate into being proficient in other things such as: visuospatial skills (though I do believe he's quite good at those too being a top level striker), attention, broader reasoning etc. It does mean you're intelligent though.
people often conflate intelligence with calculus - someone even made an Einstein reference here - I don't.