The Hardest Languages for English Speakers (and Why)

The U.S. Foreign Service Institute (FSI) has a short, blunt answer to "what's the hardest language for English speakers?". Its Category IV, which the State Department calls the "super-hard languages", has five members: Arabic, Cantonese, Mandarin, Japanese and Korean. Each takes 88 weeks of full-time training, or 2,200 class hours, to reach professional working proficiency. That's more than three times the 690 hours FSI gives for Spanish.

This post covers what makes each one hard, what 2,200 hours means for someone studying around a job, and a few languages people often assume are on the list but aren't.

On this page

FSI Category IV at a glance

Source: the State Department's Foreign Language Training page, checked September 2026, which describes them as "languages which are exceptionally difficult for native English speakers". FSI describes a typical week as 23 hours of class and 17 of self-study, so 88 weeks is closer to 88 × 40 = 3,520 hours of total effort.

The U.S. military's language school agrees on the grouping. The Defense Language Institute runs Modern Standard Arabic, Mandarin, Japanese and Korean as 64-week courses, against 36 weeks for French and Spanish.

Why each one is hard

None of these languages is hard for a single reason. Each stacks several things English speakers have never had to learn, and the hours go into all of them at once.

Arabic. A new script written right to left, in which short vowels are usually left out, so you have to know a word to read it aloud. Vocabulary is built from consonant roots slotted into patterns, which helps later but means few words look familiar early on. Several sounds have no English equivalent. And there's diglossia: Modern Standard Arabic is used for writing, news and formal speech, while daily conversation happens in regional dialects that differ a lot from it and from each other. More in our Arabic hours guide.

Mandarin. Tones (four, plus a neutral tone) change the meaning of a syllable, and the writing system has thousands of characters that give only partial hints about pronunciation. Grammar is comparatively simple: no conjugation, no cases. The difficulty is in the sounds and the script. See how many hours to learn Mandarin.

Cantonese. Everything that's hard about Mandarin, with more tones and fewer learner materials. Formal writing in Hong Kong follows standard written Chinese, which is closer to Mandarin than to spoken Cantonese, so reading and speaking don't line up as neatly. Our Cantonese vs Mandarin guide compares the two.

Japanese. Three scripts used together: two syllabaries (hiragana and katakana) and kanji, with 2,136 characters on the official list for general use, most with more than one reading. Verbs go at the end of the sentence, particles mark what each noun is doing, and politeness levels change verb forms and vocabulary depending on who you're talking to.

Korean. The alphabet, Hangul, is the quick part; most learners read it within days. The slow part is everything after: verb-final word order, particles, long chains of verb endings, speech levels, and sound changes between syllables that make spoken Korean differ from its spelling. See how many hours to learn Korean.

Which is the hardest of the five?

FSI doesn't rank within the category; all five get the same 88 weeks. The best tiebreaker is an older FSI report. In 1993, Lucinda Hart-Gonzalez and Stephanie Lindemann scored the speaking proficiency English-speaking students reached after 24 weeks of training, and economists Barry Chiswick and Paul Miller later published those scores as a measure of distance from English. Japanese and Korean scored lowest of all 43 languages (1.00), then Cantonese (1.25), then Arabic and Mandarin (1.50). For comparison, Spanish scored 2.25 and Swedish 3.00.

So if you need one answer, Japanese and Korean have the best claim to "hardest", at least for speaking in the early months. But it's one report, it's over 30 years old, and it measures speaking at a single point in the course. The honest summary is that all five take roughly the same, very long, time.

What 2,200 hours looks like outside a classroom

The "half" column uses this blog's rule of thumb that a conversational B1 level takes about half the FSI hours. It's a planning heuristic, not an FSI number. The numbers are sobering, but they're also why people who stick with Category IV languages for years tend to be the ones who tracked their hours: it's very hard to feel progress week to week, and much easier to see it in a 500-hour total.

Not on the list (though people expect them)

Hungarian, Finnish, Polish and Russian often turn up in "hardest language" lists online. FSI puts all four in Category III, at about 44 weeks or 1,012 class hours. They're hard, with big case systems and unfamiliar vocabulary, but they use alphabets that are either the same as English or quick to learn, and they're closer to English in other ways than the Category IV group. Icelandic and Navajo, two other favourites, aren't on FSI's published list at all, so any hour figure you see for them isn't FSI's.

How to make a Category IV language manageable

• Pick a milestone you can reach this year. HSK, JLPT and TOPIK levels or a CEFR level give you checkpoints every few hundred hours instead of one goal 2,200 hours away.
• Fix the script early. Hangul takes days, kana a few weeks, Arabic script a few weeks more. Characters are a multi-year project; put a small daily slot on them rather than a cram.
• Give listening a fixed share. Tones, unfamiliar sounds and fast speech are where Category IV learners stall. Log listening separately so you can see whether it's actually happening.
• Track the total. LangTrack keeps a running count per language, which is the number that shows a Category IV learner they're moving.

FAQ

What is the hardest language for English speakers?

The U.S. Foreign Service Institute puts five languages in its hardest group, Category IV: Arabic, Cantonese, Mandarin, Japanese and Korean, each at 88 weeks or 2,200 class hours. It doesn't rank them against each other. In an older FSI report from 1993, Japanese and Korean had the lowest speaking scores after 24 weeks of training.

What are the FSI “super-hard” languages?

“Super-hard languages” is the State Department’s label for FSI Category IV: Arabic, Chinese (Cantonese), Chinese (Mandarin), Japanese and Korean. They take 88 weeks, or about 2,200 class hours, for a native English speaker to reach professional working proficiency.

Is Japanese harder than Chinese for English speakers?

FSI gives both the same 88 weeks. Japanese has three scripts and complex politeness levels; Mandarin has tones and a larger set of characters to read. In FSI's 1993 speaking data, Japanese scored lower than Mandarin after 24 weeks, but the difference in total time to proficiency is small next to the gap between either and Spanish.

Is Hungarian or Finnish one of the hardest languages?

Not according to FSI. Both are in Category III, about 44 weeks or 1,012 class hours, which is less than half the time FSI gives for Category IV languages like Japanese or Arabic.

Related reading: FSI Language List: Hours to Learn Every Language · The Easiest Languages for English Speakers · How Long Does It Take to Learn Japanese? · How Long Does It Take to Learn Arabic?