As someone fluent in four languages*, I agree. I would even argue that the opposite of an advantage is true. Consider this: it adds unnecessary cognitive load. When trying to think of a word, it comes to you in four different languages, which isn't helpful! I speak four languages out of necessity, not by choice. When you can focus on fewer languages, your proficiency in them improves. Although I can speak four langua…
I am also originally from Moldova and speak the same 4 languages. If I had to guess, this is fairly common in Moldova -- at least in private schools. I would say there is a very mild advantage, even recognizing vaguely similar words in other languages when traveling. I find Russian to be very useful in a way that French and Romanian aren't. English, Arabic, Chinese, Russian, and Spanish are the most "useful" as they…
It's indeed still useful when traveling to those countries that speak these languages. But that's mere few weeks per year. English could have worked anyway as everyone is becoming proficient in English.