The head shake for yes looked weird.
Also, a Bulgarian once (over 10 years ago) demonstrated the 'no' head nod for me and it was IIRC once up and back then back to original position (not like what's on that tape).

it was IIRC once up and back then back to original position

That is how we do it (with a 'tsk' tongue sound).

Yeah, I was expecting it to be like the Greek (and other Mediterranean), but it's not.

mf: The demo may have been a minimal version to show you how it worked; in our own system, after all, you can nod either once or several times.

Some friends and I encountered this problem once in talking to a Bulgarian girl (she was probably about 17 at the time, and is probably about 24 now); we asked her some question, and she answered "yes," but with a firm shake of her head. Confused, we asked for clarification, and she more firmly said "yes," and shook her head repeatedly and emphatically. (I think it seemed more identical to the English "no" head-shake than in the video you link to, but that might be my memory overdoing it a bit.) Eventually we determined that her English was fine, and she was not trying to send mixed signals; it's just that they use the opposite signals for "yes" and "no" as we do. Very confusing; and she found that she couldn't easily get herself to use the English-style signals, so ended up training herself not to nod or shake her head at all.

OT,

I sent a query to languagehat yesterday. Kindly check your mail.

During the 1st world war my grandfather was in the French navy in the Mediterranean. They ended up in Saloniki where the troops were given some shore leave, and my grandfather and some of his buddies went to explore the countryside. When it was time for a meal, they knocked at a farmhouse and tried one of the few Greek sentences they had learned in town: "ima yayas" (so he said) for "do you have any eggs?" They were answered with a smile and a vigorous side to side headshake. They tried several more farmhouses with the same result, until at last they got a nod - and found out that they had passed up a lot of eggs because they did not know that a nod meant "no" and "yes" was the side to side head motion.

Here is a useful compendium of various head nods from the Linguist List. Unfortunately they aren't all linked to youtube...

I think it is also worth commenting on the similarity of the Bulgarian gestures to those in India. Pure speculation, but there is a link to India in the Roma ...

"Ima yayas"? Τί γλώσσα είναι αυτή;

Jimmy Ho, obviously I don't know Greek - I am only quoting what my granpa said, and he was not a language expert by any means. I heard the story many times, always with "ima yayas", but that does not mean that I take these words to be correct - but apparently they were understood. I will be glad to learn a more idiomatic sentence, should I ever want to buy eggs in the Greek countryside (around Saloniki no less).

This is not Greek. Maybe Macedonian ('yayas' looks close to 'jájce')?

I forgot the quote marks around "Macedonian"; or maybe I should've written "Bulgarian" (would that be яйцо? I'm trying to guess after some quick googling). As an illustration of Thessaloniki's polyglossy at the time, the bulletin of Benaroya's Federación was published in Greek, Turkish, Judeo-Spanish and "that Slavic language" (no disrespect: I'm just unsure about the dialectal differential).

Yes, ima is 'there is/are' in Bulgarian, and I think 'Are there eggs?' would be Ima yaitsa? 'Egg' in Greek is avgo (plural avga), so it clearly wasn't Greek. (Yaya is 'grandmother' in Greek.)

All right, mystery solved.

Thanks to LH and Jimmy both. So, instead of asking for eggs, my grandpa (young at the time) was asking if there were grandmas around???

I can well believe that his "yayas" were an incorrect memory of the actual term (I heard the story many times, but decades after it actually happened). I had thought the sentence must be from a local Greek dialect, but had not considered the possibility that it was from a non-Greek language spoken in the region. So the negative nod would have been the Bulgarian one - back to where this post started.

Mind you, a lot of Greeks, especially if they were in any kind of government position, would assure you that it was a local Greek dialect, one of those rural ones that city people find hard to understand. Then if you pointed out that it sounded just like Bulgarian/Macedonian they'd get very angry.

That hurts, LH. I happen to know Macedonians who were beaten down by the Bulgarian occupant (during WWII) until they said "doborden, gospodin ofitzer", hence "proving" that they were "slavophones".

Sure, it comes from all directions. No doubt about it.

In Kerala (a region of India), there's a sort of shake of the head we use for yes, which confuses people even from nearby states.