Users can provide a list of languages that are in the image being OCRed, but these codes are not currently validated. Both engines have lists of supported languages, against which we can check the user input. We should show a friendly error when an unsupported language code is used (currently, Google will blindly accept invalid languages and return its best guess, and Tesseract will fail with a seemingly-unrelated message).
- Validate language input based on what is allowed in engine
This language is NOT supported by the OCR.