Answer:
The word suffix that has been added incorrectly is forgoten -the correct option would be forgotten.
Step-by-step explanation:
To form the participle of a verb, the general rule establishes that the suffix -ed should be added to the base form. However, there is an exception that explains this mistake: whenever the verb has more than one syllable and the final syllable is stressed, we double the final consonant before the suffix -ed. Therefore, we should double the t in forgot before adding -ed, and the correct version of the participle would be forgotten.