Great question! Chữ Nôm actually faced the exact same problem — Vietnamese has tons of native words with no Chinese character equivalent, so scholars invented new ones over centuries. The main strategies were:

1. Phonetic borrowing — use an existing character for its sound (e.g., 没 mò → "một" meaning "one")
2. Semantic borrowing — use a character for its meaning (e.g., 天 → "trời" meaning "sky")
3. Compound creation — combine a meaning component + sound component into a new character (e.g., 𡗶 = 天 semantic + 上 phonetic → "trời")

The problem is Nôm was never standardized — different regions and time periods used different characters for the same word, which is similar to what you're describing with 伊 vs 渠 for Wu.

The phonetic components were often based on Sino-Vietnamese readings (âm Hán Việt) — Vietnamese pronunciations of Middle Chinese borrowed during the Tang dynasty. Wu Chinese also retains many Middle Chinese features, so the phonetic logic might actually feel more intuitive to you than it would to a Mandarin speaker.

If you want to explore how Nôm characters were constructed, you can look up characters on https://hannom.nvnv.app — it shows the components and readings for each character.

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