I.R.I.S. Readiris Corporate 12 for Windows User Guide - Manual (Page 66)

Chapter 10 – Recognizing documents
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Recognizing documents with mixed languages
Readiris also allows you to enable mixed character sets. That way
Readiris switches languages in the middle of a sentence
automatically and recognizes English words (proper names etc.)
that occur in "exotic" languages.
Click the globe button on the main toolbar and select the required
language combination in the language drop-down list.
Note: when processing Asian or Hebrew documents, mixed
characters sets are used automatically.
Recognizing secondary languages
Next to the primary language or language combination, Readiris
allows you to select up to 4 secondary languages of the same
language group.
This is useful when recognizing multilingual documents.
Note: do not select languages that do not apply; the bigger the
character set, the slower the recognition and the higher the risk of
OCR errors.
When scanning Arabic documents, only English is available as
secondary language.
Speed-Accuracy
Select the right trade-off between OCR speed and OCR accuracy.
This trade-off is available for the Latin, Cyrillic and Greek alphabets.