Show HN: LangLearn, a GPT-powered language tutor

I started working on LangLearn after a particularly great late night ChatGPT session where I was practising Japanese.

Converting my EN->JP experience into an app has been a tad harder than expected. With potentially 3 languages involved (the English prompt, the source language, and the target language), GPT quite often gets a bit mixed up. Despite repeated "Do NOT translate this, I will translate this", it seems like the mere presence of the word "translate" will cause it to disobey and translate away. So it's required a larger amount of prompt engineering than I expected. I'm wondering if GPT4 will increase the ability to follow instructions, but I don't have access yet.

I've started adding things like:

- highlight a word or phrase to define; this can be a lot better than a dictionary because you can do entire phrases or idioms, things that might be in a dictionary in parts but not in whole

- quick responses to save you from needing to type

I'm thinking to add:

- easily view your chat history

- a button to make your chat session public so you can share it (readonly)

- a way to add words to a wordlist, then incorporate this list into the generations, and likely, a small SRS system