Well, that’s kinda what I did (except I knew a lot of the kanji in here, but I still liked to go over them again).
I wrote about my experience in more details in my level 60 thread.
I’d say it’s really good if they need the structure. If they can manage on their own, well, free options do exist, as mentioned already. That being said, if they haven’t done it so already, I feel like structure might indeed be their problem.
you could start them on Renshuu, as it allows you to say if you already know the term while you do the reveiws/lessons
Good heavens YES!
I’m far from fluent but had a fairly large vocabulary from speaking the language (poorly) since the seventies. Learning to read and Wanikani specifically were life-changing.
To be honest: “fluent” is an opinion. I’d argue that it’s hard to be fluent in Japanese if you can’t read kanji.
Someone mentioned kids learning in Japan that already have all the vocabulary. They start learning to read at the same time they start building vocabulary. 国語 involves both, it’s not separable.
I know a smaller fraction of the vocabulary words I’m learning now, but I assure you I don’t mind AT ALL seeing vocabulary words I already “know” but can’t read. They are definitely easier but it still takes time to memorize the readings (and I miss the meanings more often than you might think due to misreading).
The only argument against WK I can imagine are the way radicals are taught. They are utterly different than how Japanese learn to read in primary school. It will make it weird and difficult talking to natives ABOUT learning, but otherwise I don’t think it’s much of a problem.
How “fluent” are they? If English is their first language, I wouldn’t hesitate to recommend WK. if their first language is Japanese or Chinese then maybe not.
For me, WK is the most fun when I already know the word and learn to read it. It might be the same for your friend. Or they might hate it. Who knows. Only one way to find out…
I’d second this, why go backwards to introduce an unnecessary English component when they already speak on a native level? I’m sure there are native materials out there as well on literacy building. Additionally, it isn’t really built to filter layouts or content either so add another time inefficiency. I see the system as something that rewards beginners more with a stress on collocations which is great because you can build a lot of confidence with a jump in progress in a rather short period of time (plus they made it fun too so you are not completely defeated in studying).
On the other hand, for similar looking kanji and meaning, I don’t think the system has a great way to address this other than collecting and grinding leech piles or some assorted scripts as a heads up…but that’s it and then go stumble into reading practice. I presume this will be a major issue given they already have a high vocabulary but probably alot mixed up kanji. The only way I’ve been able to address this efficiently is actually through some handwriting practice and just building the muscle memory on the stroke order. Think this would be time better spent + finding or making mnemonic isn’t hard if preferred. And since their ears are faster than their eyes, they probably can close a faster gap listening while reading along JP subtitles on alot of content…this would probably be time better spent.
I would think it would certainly work for him, think of it like this, the vocabulary, he may know, but does he know how it looks like in kanji form? Based on what you say, clearly not. If he wants to be literate and read in Japanese he needs to know these vocabulary in their kanji form.
Yeah, that’s the thing. She knows the words when heard, but doesn’t recognize the kanji with the exception of very basic ones. I think I’m going to recommend that she tries it out, at least for the first few levels, and if it gets frustrating, well then okay. But if it’s doable, then awesome. And I feel like the first few levels would be the biggest test, since you’re learning more common kanji (for a native English speaker, that is).
I spoke Japanese to a decent level before starting Wanikani. I’d say around 75% of the vocab I have covered in Wanikani, I already knew.
It’s actually really fun learning the characters of words you already have in your vocabulary. Connecting the dots between reading and meaning is immensely satisfying.
It’s definitely easier as well. Especially for common words that have unusual readings. I always think when I get to words like 欠伸 (あくび - yawn) what a pain it must be for most people to remember those readings, but its such a commonly used word that I didn’t have to make any effort at all.
I can pretty much guarantee that she will learn a few new words as well (especially useless baseball terminology that for some reason has been cropping up in the late level 30s 
My Japanese wife has never heard of these terms!)
I highly recommend it!
With a reorder script to do kanji first, and then vocab at whatever pace you feel like? It’s probably not a bad call. It will still have a nice structure and order, and the option to run through some vocab for context and reinforcement.
Of course, I see I’m pretty late to the discussion. Just my take though.
Oh, very.
Think the last time I had that happen was when I came across 連盟 in level 36 - as in, 灰羽連盟
Though to a lesser extent, there’s also the time I worked out the 覇 in 覇権 from level 52 is also in 那覇, the capital of Okinawa.
If your friend does decide to try WK, I’d recommend she download the keisei semantic-phonetic composition script. I think that script used in conjunction with WK adds a lot of value that most other kanji teaching tools don’t offer.
Sacrilege! 
That reminds me of another surprising thing thing happened to me more than a few times: I learned a “new” vocabulary word and only several reviews later did it actually click that it was a word I’ve heard and used multiple times! You can almost feel things shifting around in your head when that happens.
This is precisely why I believe it’s difficult to truly be fluent in the language if you can’t read it. There are connections and subtle nuances of the words that are immensely easier to understand once you can read.
欠伸 surprised me too, but almost daily I come across others. I was recently taken aback by 可哀想 — those characters made a lot more sense than what I ignorantly assumed was involved before I could read! (Mangling cute to mean pitiful didn’t make sense to me but you grow accustomed to weirdness!)
It’s hard to describe, but illiteracy is an impediment to understanding. Who knew?
100% agree on the nuance point. I feel I have much better grasp of some subtleties of meaning after learning the characters used to write certain words. Especially the shared nuance that you gain from recognizing the same character across multiple related (and sometimes quite unrelated) words.
It’s more or less my situation. I’m finding wanikani very useful also for learning the proper pronunciation (you can get away with a lot in a casual conversation).
The only thing that drives me crazy sometimes are some of the meanings… but nothing that a lot of users’ synonyms cannot solve.
I know exactly what you mean. It happens occasionally that a Japanese word or phrase can be said umpteen different ways in English and trying to remember which one WK uses can be maddening. Or it’s a common but uniquely Japanese word without an exact equivalent.
That’s the main downside to having to provide meanings for words you already know, but user synonyms suffice as you said (I’ve added romaji for more than a few words that I already know well but can’t remember what WK wants).
This is my moment to shine. I was actually closer to your friend’s situation. I wasn’t (and am not) fluent but I studied and used the spoken language for over a year before I started working on writing. What I can say for me personally, already knowing all of the vocab helps immensely. I think I would be seriously struggling without that existing foundation just because I’m not a big fan of the SRS system of WK. But thankfully since I DO have that foundation, I can say I’m completely satisfied with WK and what it teaches.
Edit: Now reading some of the comments, I see one complaint that I agree with. Sometimes the definitions that WK has are a little off from what I saw & learned from most other sources (I check my translations across multiple sources) and that has been a consistent pain point where I keep getting certain things wrong because I know them as being slightly different. But those instances are so far and few between that it doesn’t really bother me.
yes exactly! I was a bit wary at the beginning, but I kept making mistakes on words that I used everyday, so now I just put down all the synonyms and romaji that I need for the words I know. 
Same with the radicals, I put “r” as synonym for all the confusing ones after the guru level.
But it’s still super useful, I’m surprised of how it’s becoming easier and easier to learn new kanji and new words every week. After 6 months I’m at level 20 without almost any effort.
My only rule is to do it every day and never more than 20 lesson a day and never more than 100 in apprendice status.
I had told myself I didn’t need to read kanji because I can speak Japanese. I was doing okay once I got to Japan because it was okay to ask for help so often due to the cultural differences but as soon as I took one step into a grocery store, or any shopping area I was at a complete and utter loss. It was frustrating having my coworkers write to me in only hiragana, be surprised when I couldn’t read anything, and then hearing the sighs of frustrated workers at the places I shopped regularly at get annoyed with me constantly asking for them to tell me what thing I was holding.
The only way that kanji has stuck with me as well as it has is through wanikani. I get excited seeing vocab I already know, and then it helps the vocab stick even better now that I can actually disect the word and figure out what it means for a second time. I remember my coworkers faces light up at seeing that I could read the name千葉 because of wanikani. It actually feels like I can tackle kanji, so yes I would recommend wanikani to an illiterate japanese speaker if english was their first language.
I would just use maybe some scripts to allow synonyms to be placed while you learn the radicals because those are a little rough.
You can put synonyms on radicals, no need of scripts. Ask me how I know.
I totally understand you!
I’ve moved to Japan end of last year, and I really struggled with all the written information. Even when driving there are a lot of things you need to read quickly!
Also in Japanese bookshops and libraries there are lots of interesting books that I’m too slow to read… but I’m getting there!
Level 20 is not enough to read anything but I can guess many of the missing kanji so I’m opening my possibilities. Hopefully in other 6 months I’ll be able to read it fully.