user11624: If not, what would be the easiest way to modify an open source iOS/Android wallet (eg copay) to do this?

user57658: Here is the bip39 for traditional Chinese word list.
https://github.com/bitcoin/bips/blob/master/bip-0039/chinese_traditional.txt
Also, there are some useful pages that explain how to implement Mnemonic code for generating deterministic keys as following,
https://github.com/bitcoinjs/bip39
https://iancoleman.io/bip39/#chinese_traditional

11624: <p>If not, what would be the easiest way to modify an open source iOS/Android wallet (eg copay) to do this?</p>
 57658: <p>Here is the bip39 for traditional Chinese word list.</p>

<p><a href="https://github.com/bitcoin/bips/blob/master/bip-0039/chinese_traditional.txt" rel="nofollow noreferrer">https://github.com/bitcoin/bips/blob/master/bip-0039/chinese_traditional.txt</a></p>

<p>Also, there are some useful pages that explain how to implement Mnemonic code for generating deterministic keys as following,</p>

<p><a href="https://github.com/bitcoinjs/bip39" rel="nofollow noreferrer">https://github.com/bitcoinjs/bip39</a></p>

<p><a href="https://iancoleman.io/bip39/#chinese_traditional" rel="nofollow noreferrer">https://iancoleman.io/bip39/#chinese_traditional</a></p>
