15. A system comprising: one or more processors and one or more computer storage media storing instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising: receiving (i) a digital representation of text in a particular script, and (ii) a label that indicates Unicode points that correspond to the text; generating a set of graphemes based on the label; for each grapheme in the set of graphemes: determining a set of candidate recognition units that form the grapheme; selecting, from among different recognition identification criteria that are associated with different scripts, one or more recognition identification criteria associated with the particular script; applying the one or more recognition identification criteria associated with the particular script to the set of candidate recognition units to identify a training set of recognition units that form the grapheme; and training a text recognizer to separately recognize the recognition units that form the grapheme, in the training set, in subsequently received digital representations of text in the particular script.
20. The system of claim 15 , wherein training a text recognizer to separately recognize the recognition units of the training set in subsequently received digital representations of text in the particular script comprises: generating a second set of candidate recognition units from the subsequently received digital representations of text in the particular script; and determining that the second set of candidate recognition units match the recognition units of the training set.