I have been doing that for about three years, now, using symbolic characters (kinda inspired by the rapscallions proposed by Lynne Kelly). You may be interested in the posts I’ve written about that.
And a follow up:
I’ve already codify more than 1900 words in my mnemonic language, all of them used in one or more memory palaces. Each new memory palace requires less new words, but also each new topic I study/memorize has generally a lot of new keywords. I think I’ll always have more words to codify, but the need for new ones will slow down a lot.
The last memory palace I created, I had to codify 12 new words, and used 35 words already in my language.
I work on my language every day, using Anki, reviewing 55 words on average each day, which takes me less than 8 minutes, also on average.
I don’t know if this would be appropriate for others, since requires a lot of consistency, but I decided to make memory a practice and a part of my routine, so it works great for me.
Feel free to ask any questions.