Package translate allows, as of Nov 2022, to translate arbitrarily long texts using the reverse-engineered, unsupported Google Translate web API (batchexecute).
Special thanks to @Boudewijn26 for the reverse engineering work documented at: https://github.com/Boudewijn26/gTTS-token/blob/master/docs/november-2020-translate-changes.md
See Go Documentation