That's a somewhat unrealistic definition of 'professionally' but it depends on exactly what level of language-lawyering prowess you have in mind. Regardless, your original statement strikes me as a strange assertion to make to a diverse group of strangers. For many people with long careers, reaching this level in 6 languages is practically inevitable. I'm only 20 years in, and already up to 4 or 5, due solely to experience at professional day-jobs.
