They still live in Transylvania, and they are (in their own minds) the most Hungarian of the Hungarians. I’m not aware of any other populations or languages among the Szekely. They pride themselves on maintaining their language and culture ever since they were cut off from the rest of Hungary after WWI.
Somebody above (and way back when) mentioned that he might speak Turkish, which makes sense. What other foreign languages would a Romanian nobleman of his period be expected to speak? German? French? Latin? Greek?
Greek and Arabic were the languages that dominated the region nearby in the centuries preceding. Possibly he knew those as well.
You are batty!
That is some shocking parenting.
In Stoker’s book Dracula spoke English very well. Dracula made an effort to get rid of any accent so that he could move about London without anything thinking him a foreigner.
As a convert to catholicism he would definitely know some Latin, probably beforehand as the euro language of diplomacy before French took over. He married a Hungarian.
Wiki suggests he learnt Old Slavonic, Latin and German as a child; and Turkish and the Quran as a hostage. He was highly accomplished.
The Germans never liked him much.
Unlike what you might think, those names are pronounced not very much alike. In hungarian, the [sz] is an /s/ sound, and the [ly] is a soft l (the y modifies the l and is not a vowel). Szekely, then, is pronounced not as ‘shekely’ but as ‘say-kel’ (sorry, can’t be bothered to figure out the IPA on that). Which is why CK actually makes some sense.
German, Latin, Church Slavonic, Wallachian/Daco-Romanian, Magyar, and Turkish, and the actual Dracula probably had some knowledge of each of those languages.
As a boy, he would have learned Latin, Church Slavonic and German. As a teenager, he was sent to the Ottoman court as a hostage, and would have learned Turkish. His knowledge of Magyar is supposition, but the Hungarians were a major presence in his life, and he was imprisoned by them for at least 10 years.
But the sunglasses gave him away.
There werethree of them. 
No almost about it. Vlad and his brother, Radu, spent several years as hostages in the Ottoman court, and were tutored in Turkish and the Koran, so you can probably add a bit of Arabic as well.
Actually, “ly” is usually pronounced the same way as “j” in Hungarian (a “y” as in “yellow” sound), so Székely is more like “SAY-keh(y)” or “SAY-kay.”
Or, just hear it here.
I should add, regarding the Hungarian pronunciation of “ly”:
There may be some dialects that preserve the distinction between “ly” and “j,” but not any of the ones I’m familiar with. (Wikipedia states some northern dialects of Hungarian preserve this feature.) In standard Hungarian, ly=j much in the same way as ll=y in many Spanish dialects. Also, very occasionally, “ly” will be pronounced as “li” (as in the name Thököly.)
Since this is GQ some factual information will help. The real life Dracula, and other actual undead vampires don’t need to speak specific languages to communicate. They can enter the mind of a mortal and control their thoughts at level beyond language. Anyone might perceive that Dracula speaks to them in English, Chinese, or Swahili, but in reality it is just manipulation of the mind through telepathic powers.
You may now return to your random unsupported speculation.
It wasn’t long ago that I learned that, up through end of the second World War, there was a German speaking region of Transylvania. As early as 1944, though, the German government began to relocate these Siebenbürger Saxons, as they were called, to Germany proper. Surprisingly, then, for Hollywood to place German-speaking aristocratic research physiologists in the middle of Transylvania wasn’t as ridiculous as I’d thought.
Even today there’s a significant German-speaking minority in the region.