Are there only mnemonics for individual characters and not for words?

On the iOS app, that's almost true: it doesn't show the word-level ones, just the char-level ones. (If you have personally written/chosen a word-level mnemonic but not a char-level mnemonic, it might show up on the iOS app.)

On the web, you can have mnemonics for both levels, but hardly anyone uses the word-level ones compared to the char-level ones. (Which is why we didn't really put them in the app.)

Is it a simple thing to add? I feel like they are not very easily seen which is why they are not really used. I started using memrise and this was a great way for me to remember the meanings, but i don't like its recent changes. I use skritter mainly for the writing and tone memorisation but would be great if I could learn everything in one place. Maybe having the mnemonic show up underneath the meaning when you reveal it would give people a better, easier chance to view it.

If you want to use word-level mnemonics for when doing definition and reading prompts prompts, they're already in. The complicated thing we haven't done is offering both word- and char-level mnemonics in writing and tone prompts. The interface for that would not be simple.

I wouldn't use either, but my suggested interface (only when you're on a multi-character word that has a mnemonic) would be to change the pulldown into 2 pull-down buttons, 1 on left & 1 right side of screen.

Buttons would be labeled "W" and "C" (can probably use similar styling as current pull-down) and would pull down related mnemonic.

not 100% intuitive, but not particularly complicated.