Some languages take four times longer to learn than others. According to the US Foreign Service Institute (FSI), the hardest languages to learn for English speakers are Japanese, Mandarin, Cantonese, Korean, and Arabic. Each demands around 2,200 class hours, compared with roughly 600 for Spanish or French.
In this guide, you will find the FSI ranking explained, the specific reason each language is hard, and the best tool to start each one, with pricing as of July 2026.
How the FSI ranking works
The Foreign Service Institute trains American diplomats before they go abroad. Over more than 70 years, it has tracked how long its students need to reach general professional proficiency in speaking and reading. From that data, the FSI groups languages into four categories, from around 600-750 class hours to 2,200.
Two caveats matter before you read the numbers. First, these are classroom hours with trained teachers, in intensive full-time courses. A self-guided learner studying one hour a day should expect a longer calendar, though the ratios between languages still hold. Second, the ranking measures distance from English, not absolute difficulty. Hungarian is brutal for an English speaker and easy for a Finn.
For a full breakdown of what these hours mean for your own schedule, see our guide on how long it takes to learn a language.
The ranking at a glance
The table below covers the five Category V languages plus the four Category IV languages the FSI flags as unusually hard. For each, we name the single biggest obstacle and the best tool to tackle it first.
| Language | FSI class hours | Hardest part | Best tool to start |
|---|---|---|---|
| Japanese | 2,200 | Three scripts, including 2,000+ kanji | WaniKani |
| Mandarin Chinese | 2,200 | Characters plus four tones | Pleco |
| Cantonese | 2,200 | Six tones, few learning resources | Pimsleur |
| Korean | 2,200 | Verb endings and honorifics | Talk To Me In Korean |
| Arabic | 2,200 | Diglossia: standard vs spoken dialects | italki |
| Finnish | 1,100 | Fifteen grammatical cases | LingQ |
| Hungarian | 1,100 | Agglutinative grammar, 14 vowels | Drops |
| Thai | 1,100 | Five tones plus a unique script | Anki |
| Vietnamese | 1,100 | Six tones, subtle vowel contrasts | Preply |
Category V: the hardest languages to learn (2,200 hours)
The FSI calls these “super-hard languages,” exceptionally difficult for native English speakers. All five require about 88 weeks of full-time study, and one of those years is usually spent in the country.
Japanese
Japanese is often cited as the single hardest of the five, and FSI course data supports that view. The writing system combines three scripts: hiragana, katakana, and more than 2,000 kanji borrowed from Chinese. Moreover, grammar runs backwards from English, with verbs at the end and particles marking each word’s role. Politeness levels (keigo) add a further layer, because the same sentence changes shape depending on who you address.
The kanji wall is where most self-learners quit. Therefore, start with WaniKani, a web app that teaches radicals, kanji, and vocabulary through mnemonics and spaced repetition. The first three levels are free; subscriptions start at $9/month, with a $299 lifetime option, as of July 2026.
Mandarin Chinese
Mandarin pairs a character-based writing system with four tones, so you face two separate mountains at once. Reading a newspaper takes roughly 3,000 characters, and each one must be learned individually. Tones are the second obstacle: “ma” can mean mother, horse, hemp, or a scolding, depending on pitch. The grammar, in contrast, is refreshingly simple, with no conjugations, genders, or plurals.
Every Mandarin learner needs Pleco from day one. It is the reference Chinese dictionary app, with handwriting recognition, audio, and optical character lookup. The core app is free; add-on bundles start at around $30 one-off, as of July 2026. Pair it with a flashcard routine from our guide to the best flashcard apps.
Cantonese
Cantonese shares characters with Mandarin but is a different language, not a dialect. It uses six tones instead of four, and colloquial Cantonese is written with characters that standard dictionaries often skip. The bigger practical problem, however, is scarcity: quality courses and graded content are far rarer than for Mandarin.
Because listening and tone perception matter most early on, start with Pimsleur, one of the few major platforms with a full Cantonese audio course. Subscriptions start at around $20/month, with a free 7-day trial, as of July 2026.
Korean
Korean looks like the easy one at first. Hangul, its alphabet, is famously logical and learnable in a weekend. The difficulty hides in the grammar: verbs take long chains of endings that encode tense, mood, formality, and the speaker’s attitude. In addition, honorifics force you to track social hierarchy in every sentence, and pronunciation shifts at word boundaries make listening harder than the spelling suggests.
For structured self-study, Talk To Me In Korean is the strongest specialized resource. Its grammar curriculum runs from absolute beginner to advanced, with podcasts and books built by Korean teachers. Plans start at around $13/month, as of July 2026.
Arabic
Arabic’s script is learnable in a few weeks, despite its reputation. The real challenge is diglossia. Modern Standard Arabic (MSA) is the language of news and formal writing, yet nobody speaks it at home. Instead, people use regional dialects, and an Egyptian and a Moroccan may struggle to understand each other. Consequently, learners must effectively study two languages: MSA for reading, plus one dialect for conversation.
That choice is why we recommend starting with a human. On italki, you can filter tutors by dialect (Egyptian, Levantine, Gulf, Moroccan) and build speaking habits from week one. Community tutors start at around $8/hour, as of July 2026.
Category IV: the hardest of the rest (1,100 hours)
Category IV contains about 50 “hard languages,” from Polish to Hindi to Turkish. Within it, the FSI flags a handful with an asterisk as typically more difficult for English speakers than others in the group. Four stand out.
Finnish
Finnish belongs to the Uralic family, so almost no vocabulary transfers from English. Its grammar uses fifteen cases, and words change form so much that a dictionary lookup can fail on an inflected word. On the bright side, spelling is perfectly phonetic. Massive reading input helps more than drills here, which makes LingQ a strong fit: it turns native texts and podcasts into interactive lessons. A free tier exists; Premium starts at $12.99/month, as of July 2026.
Hungarian
Hungarian, another Uralic language, builds words by stacking suffixes: one word can translate a full English clause. It also has 14 vowel sounds and vowel harmony rules that decide which suffix fits. Vocabulary is the long grind, since nearly everything must be learned from scratch. Drops covers Hungarian with fast visual vocabulary games, five minutes at a time. The daily free session costs nothing; Premium starts at around $10/month, as of July 2026.
Thai
Thai combines five tones with its own script of 44 consonants and complex vowel marks, written without spaces between words. Grammar, meanwhile, is mercifully simple: no conjugation, no plurals, no cases. The script and tones are pure memorization work, which is exactly what Anki does best. Community-made Thai script decks with audio are free, and the app costs nothing on desktop and Android ($24.99 one-off on iOS, as of July 2026).
Vietnamese
Vietnamese uses the Latin alphabet, which fools learners into underestimating it. Six tones and unfamiliar vowel contrasts mean that self-taught pronunciation often drifts into something native speakers cannot parse. Early human feedback is therefore the highest-leverage investment. On Preply, Vietnamese tutors start at around $5/hour as of July 2026, cheap enough for two short sessions a week.
Hard does not mean impossible
Do not read this ranking as a warning list. The hours measure distance from English, and every one of these languages is learned to fluency by thousands of ordinary people each year. In fact, the hardest languages often deliver the biggest payoff. Mandarin, Arabic, and Japanese open professional doors precisely because so few English speakers persist.
Difficulty is also front-loaded in specific, solvable problems. Kanji yields to spaced repetition. Tones yield to feedback and listening volume. Arabic diglossia yields to picking one dialect early and sticking with it. As a result, the right tool for the right obstacle matters more here than anywhere else in language learning.
If you want maximum results for minimum hours instead, start from the other end of the scale with our guide to the easiest languages to learn.
The bottom line
Japanese, Mandarin, Cantonese, Korean, and Arabic are the hardest languages to learn for English speakers, at roughly 2,200 FSI class hours each. Finnish, Hungarian, Thai, and Vietnamese lead the 1,100-hour tier behind them. Each language is hard for one dominant reason, and that reason should dictate your first tool.
Our recommendation: pick the language you actually care about, then attack its specific bottleneck from day one. Scripts and characters call for an SRS tool like WaniKani or Anki. Tones and diglossia call for early human feedback on italki or Preply. To compare more options for your target language, see our guide to the best AI tools for language learning.