I made an analogy in another thread with Normans of Duke William. Bulgars were the ruling elite and apparently they were not as numerous as Slavs. After Christianization and adoption of Cyrillic alphabet Bulgar language became extinct on the Balkan peninsula. We have several words from them in our modern vocabulary like kuche /slavic pes/ translation dog. How numerous were Visigoths & Suebi in comparison with local vulgar latin speaking population during their migration into Iberian peninsula?