If you have a ChatGPT subscription, set up your own GPT with prompting around your level, how you want it to respond, how to correct mistakes etc. Then you can use it for anything - Generate tests based on words you know, roleplay like ordering in a restaurant, write stories and have it correct grammar.

This is what I have to supplement my Chinese and it is incredibly helpful.

Look at the comments already - Everyone is building a simple wrapper to do this very thing but charge you $20 per month for the privelege. These are souless, most likely vibe coded garbage. Avoid.

I'm learning Finnish. For the most part, Gemini and ChatGPT do a much better job at generating passable if sightly Internet-inflected Finnish than I'm likely to anyway within the next 5 years, so I just talk with those.

I would imagine Dutch to be in the same camp, unless a native Dutch speaker reviews some of your conversations and tells you otherwise. My native Finnish wife has given me the marginal all-clear with the vanilla models.

I added a Practice Mode in my speech-to-speech translator app 3PO. It allows you to practise talking with chatGPT and gets assessment score on your accuracy.

Topic is preset. (chatGPT plays the role of a travel guide to help you find places to go in Holland (for Dutch))

https://3po.evergreen-labs.org

I've been setting up Vapi.ai for this. Written and spoken are different skills. It comes down cheaper than an actual teacher, and it has the patience to correct you.

I’m making fluent.im, it has situations with goals for each conversation, and we’re about to ship lessons based on your favorite podcast content.