Is Japanese FSI Category IV or Category V? Both, and that is the problem

Two incompatible numbering schemes for the FSI difficulty categories are in circulation, and neither is wrong. Which one a page uses tells you whether it copied its data or checked it.

Aug 8, 2026Kevin Fan

Look up the FSI language difficulty categories and you will find Japanese described as Category IV on some pages and Category V on others. Chinese likewise. German is Category II in some tables and Category III in others.

None of these pages is lying. Two numbering schemes are in circulation, and most pages using either have no idea the other exists.

The two schemes

The State Department groups languages by how many class hours its own students need. The hour bands are stable and uncontroversial. The numbering of those bands is not:

Class hours	Four-tier scheme	Five-tier scheme
600	Category I	Category I
900	Category II	Category III
1,100	Category III	Category IV
2,200	Category IV	Category V

The difference is whether German gets a category of its own. In the four-tier version German sits at Category II, one band up from Spanish. In the five-tier version, a Category II is carved out for a small group and German lands at III, pushing everything below it down a number.

So "Japanese is Category V" and "Japanese is Category IV" are the same claim about the same language in the same band, said in two vocabularies.

Why this matters more than it looks

Because the number is what gets copied, and the hours are what mean something.

A page that says "Category IV" without an hour figure is unusable: you cannot tell which scheme it is on, so you cannot tell whether it means 1,100 hours or 2,200. That is a factor of two, and it is the difference between eighteen months and three years.

This is also a decent test of whether a page checked its sources. The State Department publishes its category chart as an image, so per-language assignments circulate through third-party reproductions. A page that reproduces one numbering scheme without knowing there is another has copied rather than checked.

I got this wrong myself, early: an internal document here described "FSI Category I–V" as the official scheme. It is not — the State Department's own materials use four groupings. The fix was structural rather than editorial.

What this site does instead

Everything here is keyed on hours, not on a category numeral. The model in src/lib/fsi/languages.ts stores 600, 900, 1,100 or 2,200; no code path anywhere depends on a Roman numeral.

Where a category label is displayed, both schemes are shown, because a reader arriving from a page using the other one needs to be able to reconcile them.

That is not fastidiousness. A numbering scheme is an identifier for a band, and the band is the fact. Keying on the identifier means inheriting somebody else's ambiguity forever.

The practical version

When you meet an FSI category number anywhere:

Ask for the hours. If the page does not give them, it cannot be reconciled with any other page, and you should distrust it on principle.
600 / 900 / 1,100 / 2,200 are the real quantities. They are what FSI publishes and what everything else is derived from.
A page quoting a category with no hours has not checked its source. Sometimes it is fine anyway. It is still worth knowing.

The full table for thirty languages, with hours and both numbering schemes, and where the figures come from.

Posts resting on the same evidence, picked by shared citations rather than by hand.

The Arabic course you buy is nobody’s native language
Modern Standard Arabic is what almost every course teaches and what nobody grows up speaking. Decide which Arabic you want before you spend 2,200 hours, because the choice is not reversible for free.
Dutch is the easiest language to learn and the hardest to practise
Same FSI band as Spanish, closer to English than anything else on the list, and almost every person you would practise with speaks better English than your Dutch. The obstacle is not the language.
The 3,000-word claim is measuring something else
Nation (2006) puts unassisted comprehension of written English at 8,000–9,000 word families, and spoken English at 6,000–7,000. The 3,000 figure is real, sourced, and answers a different question.

Sources

Every figure above, and where it came from. A post that traces other people's unsourced numbers does not get to have any of its own.

Foreign Language Training — US Department of State, Foreign Service Institute
The class-hour bands every estimate on this site starts from, and the definition of the proficiency they lead to (ILR Speaking-3 / Reading-3).
FSI Language Difficulty Ranking — fsi-language-courses.org
Which languages sit in which band. The State Department publishes the categories as an image, so per-language assignment comes from independent reproductions that agree with each other and with the official hour bands.