In my limited knowledge, Slavic languages appears to be closer to Sanscrit than the Germanic ones. For example, ogon'-agni for fire or the root ved for knowledge. I wish I knew more about it, though.
It's really impressive that you can handle all those very different languages. Beyond the ones I grew up with and English, I can make rough sense of most of the Slavic ones, have some rudimentary Hebrew, and can decipher something simple in Romance languages, but I could not even take a stab at the tonal languages. I have a good eye for language but a dismal ear.