In French, you say C'est du chinois (litterally, ‘It's Chinese') when you want to express how much what you've heard or read is just so unintelligible. A few hundreds years ago, French people were saying C'est de l'hébreu (‘It's Hebrew'). In English, you say ‘It's all Greek to me'. In Swedish, you say Det är rena grekiskan or Det är rena arabiskan (‘It's pure Greek' or ‘Arabic'). We may infer from these sayings – and there are many others – that there seems to always be a consensus on which is the hardest language to learn for a population at a given moment.
Now, of course, no language is difficult per se. Babies learn them ! Every language is an addition of little pieces of information that form a big jigsaw puzzle. The puzzle is big – huge in fact – , but you just need to be perseverant and add one little piece of the jigsaw puzzle after another until you can say one simple sentence and then another one. Languages may have a lot of exceptions to their grammatical rules, you still just need to learn the rules, the exceptions and then use them all in the most inadvertent manner possible. It takes time and effort for sure, but that’s all there is to it really.
That said, there are languages that present more difficulties in one area or another. Those difficulties are principally found on the grammar side. Let’s look at those a little closer.
I. The hardest grammatical areas of languages
Linguists classify languages into six main word order categories. From the most used to the least one, those categories are: SVO (Subject / Verb / Object), SOV, VSO, VOS, OSV and OVS. The English language for example pertains to the SVO type, which means that people usually (not always, far from it) construct their sentences putting the grammatical elements called subjects first, those called verbs second and the ones called objects third. Of course, we do this mental gymnastics without much thinking about it. It’s when we start to learn a language that has another word order than the one of our first language that this habit makes itself be noticed. However, the gymnastics in question only consists in repeating a sentence scheme often enough so as to get the hang of it. It may seem difficult at first, but it doesn’t take much time to get the habit right.
Declensions are in my opinion another animal entirely. My first encounter with them was when I started learning latin at school in France. If I remember well, it was still a required course back then. Well, all those different endings for any single word ! Seven endings for a word depending on how I was going to use it in a sentence. Plus seven more for the plural forms of course. A rose ? Rosa. I’ve bought a rose ? Rosam. The petals of the roses ? Rosarum. But it was not over: these declensions worked with rosa types of words only. There were (there still are, you can check) four other types of words with their own declensions. Plus a few exceptions. No kidding ! I loved school …
Grammatical genders are noun categories that define how others words, such as articles and adjectives, should behave in interaction with the nouns. One gender category, one kind of action. For example, in French, you would say Le jardin est vert (jardin is masculine) and you would say La maison est verte (maison is feminine).
Grammatical genders come in all kinds and sizes. To start with, feminine and masculine genders are not very clear-cut categories. Some words may be feminine in a language and masculine in another one. There is no right or wrong, it’s just like that. Besides, like in Rumanian, some words are masculine in the singular and feminine in the plural … In some languages like Turkish or Indonesian – and, it may be surprising, but those happen not to pertain to societies that are presently known for being the most respectful of human differences – there are no grammatical genders, no masculine or feminine nouns nor even such pronouns. Male and female human beings are referred to in the same way, with the same words.
In the Supyire African language, mostly spoken in Mali, there are five genders that separate human words, big things and animals, small things and animals, “collectives” (words such as ‘earth’ or ‘happiness’) and liquids. In other languages, you will even find gender categories for edibles or for long objects.
Verbal systems can very much look like noun declensions. In French for example, the verb aimer, ‘to love’, is composed of its root aim and the two letters er, which indicate that this verb is a first group one. There are three groups of verbs and each one has its own way of “declining” or “conjugating” its verbs. In addition to deciding which group a verb pertains to, the difficulty in using French verbs then resides in choosing what tense to use and then what ending to add according to the subject of the sentence. Nous aimions (that is, ‘We loved’) for example, is a first group verb conjugated in the simple past tense at the first person of the plural … thus giving aim + ions.
The English verb system is simpler. That’s one great news teachers usually don’t forget to tell their students when giving their first lesson to them: yes, there is a list of irregular verbs to learn by heart, but it’s not too long and as for the rest, verb forms don’t change much. You only add a little ‘s’ at the third person of the singular in the present tense, a little ‘will’ in the future tense, a little ‘ed’ suffix for the past and that’s about it!
As a general rule, the more information stuffed into the verbs of a language, the hardest it will be for you to learn. One such language is the aboroginal language Matsés, spoken in Peru and Brazil. It requires people to give so acute precisions that no other language you may know can compete with it. There are in fact little chance that every time you use a verb, you’re already in the habit of specifying when happened what you’re talking about and how exactly you came to know about it. Was it within the last month, the last fifty years or even before that ? And were you there when it happened ? Or did you only see a proof of what you’re talking about ? Or are you just making an assumption ? Or still, have you heard about it from someone else ? You don’t know ? Well, that’s too bad ! Because if you want to blurb your first Matsés sentence out, even the simplest one, you’ll have to specify the facts and your sources by adding little morphemes to your verb …
And a few little precisons about space …
Guugu Yimithirr, spoken in the northeastern region of Australia by less than a thousand persons, is another interesting piece if you’re looking for the hardest language to learn. It uses the four points of the compass instead of the egocentric coordinates that English or French use. Concretely, this means that Guugu Yimithirr speakers always know where their north is. They have developed a spatial sense that allow them to tell you without a fail that the bathroom is towards the south-west (instead of on your left or right). Good luck with that one !
II. Speech speed and pronunciation subtilities
Grammatical areas aren't however the only things that make a language more or less difficult to learn. Understanding oral speech is another factor that comes into play. To start with, our ears may take some time to get used to a quicker speed of talking. Some languages are in fact spoken more rapidly than others. You can also not be much acquainted with particular sounds. Differentiating between similar-sounding sounds may be tricky. The word agujero for example, which means ‘hole’ in Spanish, is a word that has yet to pass through both of my ears before I can even consider trying to pronounce it. I hear well that the ‘g’, the ‘j’ and the ‘r’ are pronounced differently, but as long as my ears won’t be more accustomed to these sounds, I think I’ll keep on saying them the French way (“agu-urero”) …
III. OK, OK ! Here is the hardest language to learn ever
Now if your goal is to get your hands on the hardest language to learn that ever existed, your motivation is another important, determining factor. Of course, if your motivation is to think with delight that you are for sure going for the most difficult language of all, then, thumbs up, you’ve got the power, everything is possible ! If you decide for example to learn a tongue that has no written records, a language that is only spoken, you will have chosen a hard one to learn for sure. And if you want to go one notch further, you can inversely choose to learn a language that has written records, but records that have not yet been deciphered. You could then decypher the writing, the vocabulary and the grammar. I've personnally never tried, but that must for sure be the most satisfying way to learn a language!