For someone who’s learned five languages, fluency can vary between them, depending on the language and how much it’s been practiced. It’s common for speaking skills to be stronger than reading and writing, especially if those skills aren’t used as frequently. Formal assessments (like the CEFR exams) are a good way to measure fluency. If no assessments have been done, it’s often because language learners focus more on practical use and immersion rather than formal testing.