I.R.I.S. Readiris 14 for Mac User Guide - Manual (Page 55)

Section 5: Selecting the Recognition Options
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Selecting the language per page
When specific pages use a different language than the overall
document, you don't need to define a secondary language. You can
apply a different language to those pages.
Select the pages in the Pages panel, Ctrl-click them and use the
command Language to assign another language than the overall
document language to that/those page(s).
Pages with a different language than the overall language are marked
in red in the Pages panel.