Makes or becomes crispy, used in third person singular (he/she/it crispens).
Present tense third person singular of 'crispen,' formed by adding '-s' to the verb stem. This is how English marks that someone other than 'I' or 'you' is doing the action.
The simple '-s' ending for he/she/it is ancient English, borrowed from Old English verb patterns that are still visible in languages like German (sprechen → er spricht).
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