Verbs ending in a consonant followed by -y change the -y to -ied in the past tense form.
Decertify is regular. It follows the -ied Conversion rule.
Use past time markers: "Yesterday, she decertified to the store."
No. Use "did not decertify" (not "did not decertified").
The verb decertify follows the standard English past tense conjugation rule. When forming the past tense, decertify becomes decertified. This follows the -ied Conversion pattern, which is one of the most common conjugation rules in English.
Understanding why decertify becomes decertified helps with spelling and pronunciation. Verbs ending in a consonant followed by -y change the -y to -ied in the past tense form.
When using decertified in writing, remember that it functions as a past tense verb and typically appears with time markers like yesterday, last week, or ago. For example: "Yesterday, she decertified to the store." The past tense form does not change based on the subject — I decertified, you decertified, he/she decertified, we decertified, they decertified.