Meanwhile I see Hungarian, famous for being the hardest language to learn, is fifth least weird. Even stranger, Cantonese, which is almost exactly the same in writing as 'weird' Mandarin, is sixth least weird. How can two languages that you write the same be so very far apart in feature set?
I speak both mandarin and cantonese. I think a lot of the 'weirdness' factor comes from actually saying the words. Also there are some words in cantonese that are not in mandarin. For example, in Cantonese, there is 'mou' (the negation of having), while in Mandarin, it'd be pronounced as two words ('mei2 you3). Spoken cantonese in some regards, is easier to pick up than spoken mandarin (definitely easier to cuss in)
"Gonnae no' dae that?"
"a shprakh iz a dialekt mit an armey un flot" 
(A language is a dialect with an army and navy)
-- Max Weinreich
Saying that Moldavian is a dialect of Romanian is sort of an overstatement, because besides a couple of regional words and phrases imported from Russian, it's the same as literary Romanian in writing and when spoken we have the same accent used in the region of Romania that borders Moldova (and that's bigger than Moldova itself, we even call that region Moldova and when we refer to Moldova, the country, we're calling it Basarabia).
Romanians are also the largest population group living in Moldova. This country is basically a part of Romania that was taken from us. Unfortunately they don't want to unite with us, because many Romanians there forgot that they are Romanians or consider themselves to be Moldovans. We also help them whenever we can and we also represent their door to EU, since obtaining Romanian citizenship is easy for Moldovans. Unfortunately having them close to our hearts went without returned favours. But whatever, if they want to be Moldavian-speaking Moldovans, living in Moldova, to each his own.
Source? It's hard to determine which language is hardest to learn since it all depends on what languages you already speak.
People who are familiar with Finnish and Estonian probably won't find Hungarian too hard, because the three languages are related.
Another example: Is English hard to learn? Probably not if your native language is a Germanic one (such as Dutch), but if your native language is Japanese, English might be a serious challenge.
Turkish was the language the lower and middle Turkish classes typically used during the Ottoman period. When the language reforms came in not long after the establishment of the modern Turkish republic, they were specifically designed with the idea of unifying the people by language and being easy to learn to read and write, which is how Turkey went from a literacy rate of 30% to 70% in just a few years.
Turkish is weird to a western european, but once you get past the initial weirdness is probably the most regular and structured language you'll ever learn. Which you'll find exceptionally weird if you've ever tried to queue for a ferry ticket in Turkey (which is not regular or structured at all).
Let's put aside the fact that Cantonese has among the most complex pronunciation systems in the world, with seven tones and both long and short versions of a number of sounds. This is a language which has four different communication modes. Here's how weird Cantonese is.
1. Cantonese speakers speak in Cantonese.
2. Cantonese speakers read and write in a totally different language, namely Modern Chinese, which for all intents and purposes is Mandarin.
3. Cantonese speakers read out loud in Modern Chinese (Mandarin), but pronounce each of the characters with radically different Cantonese sounds.
4. For purposes of comic book dialogue, etc., it is possible to read and write some Cantonese using various co-opted Chinese characters. But you can't pronounce all of Cantonese this way: many words have no written form whatsoever. This has resulted in a bizarre pidgin written form. For example, one very common word ("di1" -- "a few") is actually usually written as "D" rather than as a character. Other characters are impossible to write in current fonts, or are also used in Modern Chinese but for different words than in Cantonese, and so you see Latin letters like "o" and "a" next to them to suggest a different meaning.
Mandarin weird my foot.
Don't know about Hindi, but since it's used as a lingua franca of sorts that might also be the reason behind its normalness.
1. There is not a universal definition of what defines a language and what is simply a dialect or a regional variation; this applies especially on large continents where there can be greater variation in language features between geographically remote locations, but no clean boundary at which you can say people speak one or the other language.
2. Languages evolve, diverge and sometimes borrow, and so a group of related languages can share the same potentially idiosyncratic feature because of common evolutionary roots rather than because the feature makes sense. This could explain the result for Hindi - it is a standard language that 'averages' a large number of other Indian languages.
> This could explain the result for Hindi - it is a standard language that 'averages' a large number of other Indian languages.
I think this is a little misleading; a lot of Indian languages come from a completely different language family to Hindi (Hindi is Indo-European, but a lot of Indian languages are Dravidian, e.g. Tamil and Urdu), though I'm not qualified to speak about this.
Incidentally, your comment led me to this http://en.wikipedia.org/wiki/Hindi–Urdu_controversy which you may find interesting.
English is thus - for all intends and purposes - not weird.
A more interesting approach would be to take larger languages, like English, Mandarin, Spanish, etc. and value their features higher than languages spoken by tribes or very few people, and thus you could determine a more accurate 'weirdness' index out of that.
If programming would have been developed in asia, what would be the paradigm for programming be?
Lines of code? Pictures? Left to right? Top to bottom? Objects and methods?
Any steampunk fantasies available reg. programming languages? How weird would those be?
I see this was posted overnight in my time zone. Several of the earlier comments correctly point out that empirically, a language that has been acquired by many second-language speakers (for example, English) must not strike too many people as unlearnably "weird." Many widely spoken languages have undergone a process that linguists call "koineization" (after the spread of Koine Greek as a common language of the ancient eastern Mediterranean and Near East)
in which the language simplifies some grammatical (and possibly phonological) features as it is spoken by more second-language speakers for trade or for use as a language of national administration in a multilingual region.
The United States is largely an English-speaking country, but only about one-fourth of Americans have ancestors who spoke English before arrival in North America. (Indeed, only one of my four grandparents, all of whom were born in the United States, grew up in an English-speaking household.) In other words, General American English is a koine language of second-language learners of English, so it is not surprising that it is spreading all over the world.
P.S. Feel free to visit my user profile here on HN to see more about my background in linguistics and language learning and teaching.
AFTER EDIT: Cantonese versus Mandarin as "dialects" or "languages" were mentioned in other comments. Cantonese is at least as different from Modern Standard Chinese (Mandarin) as German is from English. How you might write the conversation
"Does he know how to speak Mandarin?
"No, he doesn't."
in Modern Standard Chinese characters contrasts with how you would write
"Does he know how to speak Cantonese?
in the Chinese characters used to write Cantonese. As will readily appear even to readers who don't know Chinese characters, many more words than "Mandarin" and "Cantonese" differ between those sentences in Chinese characters.
They were lost when the Danes invaded. The language was simplified to a mutually-understandable subset.