Indeed, which is interesting, because “Slav” comes from the word for “speech” or “word”. In Polish, for example, “word” is “słowo”, whereas “Slavs” is “słowianie”. Germans are “niemcy” from “niemy”, meaning “mute”. So to be a Slav meant to be intelligible and able to speak, whereas Germans were unintelligible or “mute”. Compare this to “barbarian”, from the Greek, which comes from the sound of the unintelligible speech of foreigners to the Greek ear (“barbarbar”, almost like “blah blah blah”).