When people start thinking about learning a foreign language, one of the first thoughts that spring to mind is: “I am not going to learn [insert a language] because it is too hard.” Dismissing the thought of learning a particular language just because it is generally considered hard would be a mistake; there are many other important factors to consider. However, the idea that some languages are harder than others is, unfortunately, correct.
How hard it is to learn a particular foreign language for you depends on many different factors, such as natural talent, available learning resources, and your learning plan, but I believe the single most important factor is how closely related the language is to the languages you already speak.
Since this article is written in English, I will concentrate mainly on the difficulty of learning various European languages for English speakers and advantages and disadvantages English speakers have, but many of the ideas apply also to speakers of other languages.
English is a good starting point for Germanic and Romance languages
English vocabulary is a mixture of words coming from Germanic languages, French, Latin, Greek, and a handful of others. As a result, adjectives in English are often not derived from the corresponding nouns but rather from words originating in a different language, for example:
ten – decimal
end – final
There are many others. These are called collateral adjectives, and you can read a long list of such pairs on Wiktionary.
While this feature is not so good for English learners, it is very helpful for English speakers. It will be easy for you to remember that “hand” is Hand in German and mano in Spanish, that “ten” is tien in Dutch and dieci in Italian, or that “end” is Ende in German and fin in French.
In summary, when an English speaker starts learning a Germanic or Romance language, thousands of words will look familiar to them. Since vocabulary tends to be the nemesis of most language learners, this makes learning a Germanic or Romance language much easier than learning Slavic and Asian languages.
In terms of the ease of learning vocabulary, there are probably not significant differences between the commonly studied Romance languages (French, Spanish, Italian, Portuguese), although French should be the easiest one for an English speaker (around 45% of English words come from French, so their modern English spelling is closer to their French spelling than the corresponding Spanish or Italian spelling).
Among Germanic languages, Dutch vocabulary will likely be somewhat easier to learn than, say, German or Swedish vocabulary, because Dutch is more closely related to English, and, just like English, contains thousands of French loanwords.
Slavic languages share much less vocabulary with English than Romance and Germanic languages do, and learning the vocabulary will feel significantly more difficult. Additionally, East Slavic languages (Russian, Belarusian, Ukrainian) are written using the Cyrillic alphabet, which further increases the difficulty of learning them.
English grammar causes trouble
Even though English shares a lot of words with other European languages, its grammar is quite different. There are no grammatical genders (inanimate objects being treated as male or female), no noun declensions (we would say “of me”, not “of I”, but nothing changes between “the tree” and “of the tree”), virtually no conjugations (most English verbs have only four different forms, e.g. walk, walks, walked, and walking, while verbs in French can have over 40 different forms!), no endings for adjectives depending on gender, and the list could go on.
This makes it harder for English speakers to understand various common grammatical constructions in other European languages. This may be a problem for some; some people find it hard to accept that things that “are the same” in English must be translated using several different expressions into another language.
Nevertheless, not all languages contain the same amount of features that are missing in English. The system of conjugation of verbs in Romance languages is more complex than in English, but the principle is not hard to understand for English speakers. Romance languages also have just two grammatical genders (which is a concept unknown to English speakers).
On the other hand, in German, nouns (together with articles) and adjectives are declined according to grammatical gender (of which there are three) and case (four different cases: nominative, genitive, dative, and accusative). This tends to be a little bit harder to swallow for English speakers learning German than conjugation of verbs in Romance languages.
This is not the case, however, with North Germanic languages in Scandinavia. Swedish, Norwegian, and Danish grammar is actually even less complex than the English one (conjugation of verbs is trivial, and there are no grammatical cases of nouns and adjectives; however, there are still two or three genders). In terms of grammar, the easiest languages to learn for an English speaker are probably Swedish, Norwegian, and Danish, followed by Dutch.
Learning Slavic grammar, on the other hand, is a nightmare for non-Slavic speakers. One usually has to learn more than 10 different declension patterns for nouns, 12 or 14 cases for each of them (6 or 7 for both singular and plural). Adjectives are also declined based on gender. The system of verbs and tenses is somewhat easier than in Romance languages, but not significantly. You can read more about the difficulties here.
Note: English is not so closely related to any other language
Oddly enough, I would say that it’s actually harder for a native English speaker to become a polyglot than for speakers of other European languages. Languages within the major language families present in Europe are usually quite closely related; it is very easy for a Czech to learn Polish or Slovak and for a Spaniard to learn Italian or Portuguese.
The major European language most closely related to English is probably Dutch, but still, Germans will have a much easier time learning Dutch than the British, and it is not really worth it for an English speaker to learn Dutch (unless he or she lives in the Netherlands or Belgium), since almost all Dutch speakers also speak English. Other Germanic languages, such as German and Swedish, are much farther from English than Romance or Slavic languages are from each other.While this may seem to be the reason why the Great Britain is one of the most monolingual countries in Europe, the data shows that Continental Europeans in fact rarely choose to actively learn a language closely related to their mother tongue.
“So, what languages should I learn?”
I think there exists a “myth” in the English speaking world that Spanish and Italian are “really easy”, but this is not really the case. Spanish and Italian are probably among the easiest languages when you just started learning the language (because of simple pronunciation rules and a lot of familiar vocabulary) but I believe that when you reach the later stages of learning (when you try to attain some level of proficiency), Spanish and Italian grammar can be pretty tricky.
I would say there is not much difference among various Romance and Germanic languages in terms of difficulty of reaching proficiency as a native English speaker. German is usually considered somewhat harder than most other Germanic and Romance languages, and while this is true, it is not harder to speak German well enough to make yourself understood; it is harder, however, to speak it without making a large number of mistakes.
Once we leave the realm of Germanic and Romance languages, things start to get complicated. Slavic languages are much harder to learn than Romance and Germanic languages, and you can read my explanation of the phenomenon in a separate article. If you would like to learn a Slavic language, Slovak may be a good choice in terms of difficulty. It is slightly easier than most other Slavic languages, has quite a neutral “Slavic sound”, and it is a good starting point for learning other Slavic languages. On the other hand, it has also one of the lowest numbers of speakers in the Slavic family.
Finnish and Hungarian (which have not been mentioned yet) have very little in common with other European languages (they belong into a different language family), but they are comparable in terms of ease (or rather hardness) of learning to Slavic languages.
Modern Greek is usually grouped with Slavic languages when it comes to rating of difficulty of learning, but I don’t think this is justified. In terms of structure and ease of learning, Greek grammar seems to be very similar to German, and an educated speaker of English should already know a significant number of Greek words. The writing system should also be easy to master, since most English speakers are already familiar with the Greek alphabet to a certain degree from their maths classes.
East Asian languages are a completely separate chapter. My knowledge of these is quite limited, but it’s probably easy to imagine what could go wrong. Chinese grammar is usually considered quite simple, but its pronunciation and writing system are a real pain for westerners. Japanese has a quite European-friendly pronunciation, but its writing system is extremely complicated (even more so than the Chinese one). Korean has quite a simple writing system and phonology, but people usually consider it as hard as Chinese or Japanese..
Based on the typical experiences of learners of East Asian languages, it seems you should be able to reach fluency in three or four “easy” European languages within the same time frame you would need to reach fluency in just a single East Asian language, which is something you should take into account when you decide which language to learn.