Show HN: I built this to talk Danish to my girlfriend – works with any language

26 lil_csom 10 7/13/2025, 11:38:18 AM menerdu.vercel.app ↗

I'm in my 4th year living in Denmark as an expat, and I finally decided it’s time to properly learn Danish. I do have a Danish girlfriend, after all. One way I’ve been practicing is by trying to text only in Danish, but I often find myself stuck. I start my message in Danish, then hit a wall because I don’t know a word or how to fit something naturally into the sentence.

Especially in those cases, I used to give up and translate the entire message from English, which kind of defeats the purpose and interrupts the learning process.

So I started prompting GPT. I’d write my message with wildcards or notes for the parts I didn’t know, and it would return a corrected version. That worked well, but reusing the prompt each time became tedious.

So I built a wrapper around it.

Now I can type in the target language, mark unclear parts with curly braces {like this}, and get an instant corrected version with explanations. I also added a history feature so I can review what I got wrong, and I plan to build more on that soon (eg. summary of areas or words to review).

This app is for language learners who want to practice writing without feeling insecure about mistakes or breaking their flow by switching to a translator.

I hope you find it useful!

Comments (10)

optionalsquid · 18m ago

This is an interesting idea.

But, besides not being able to use your site due to the errors mentioned by other posters, both the examples on your website give me pause:

The example input "Kan you hjelmpe mig {yesterday}?" reads to me as "Can you help me yesterday?", but that's just a nonsense sentence and an odd choice for an example. The word for "help" is also misspelled, but presumably that would get corrected.

And the suggestion of "Jeg vil gerne handle i morgen" for "Jeg vil gerne go shopping i morgen", instead reads to me as "I would like to act tomorrow". A more idiomatic translation would be "Jeg vil gerne købe ind i morgen".

xingped · 22m ago

Well I broke it immediately, haha. Sorry about that. Apparently it doesn't like Chinese.

Alex-Programs · 11h ago

This is really cool!

I've done a lot of research into LLM translation for my product[0], and I'm currently working on a deep translation service that provides reliably human-level translations.

I don't know what model you're using, but GPT-4.1 is probably the best for your use case - it's in the top few % for nearly every language, and has a low standard deviation, while also being relatively low latency and low cost.

[0] https://nuenki.app

jmpavlec · 8h ago

Tried it with some Dutch, only getting "Unable to process correction" errors. Good idea but seems it need a bit more error handling.

sunbum · 10h ago

In the example text hjelmpe is not a word in Danish.

zamadatix · 6h ago

I assume the stuff about the AI giving corrections might apply to more than just what's in curly braces, i.e. that this might be intentional, but I'm unable to test due to a "Unable to process correction" error on the demo.

lil_csom · 18h ago

Also, yes the TTS doesn't work yet - I decided to share the MVP first before adding my Google billing account :P

gus_massa · 3h ago

I got an error. Is it working now?

Aro_oj · 13h ago

First of all, 10 points for the dedication and perseverance! The website looks super professional and promising. What other languages can it help with? I am planning to learn Arabic. Also, are there options to choose between different dialects of a language?

lil_csom · 12h ago

Hey! It should work with all the languages as it auto-detect the target and the source language - however, it might need to be tuned the bit. Eg. if you write in arabic but use English wildcards, it should work okay! About the dialects actually I haven't thought of! I think you can provide it as context, however it's probably limited to what GPT knows as I don't integrate with any official trasnlators as of now :) Interesting use-case!