Y creo que no soy tonto, tampoco.—RAMOS CARRIÓN.
When either at the end of a negative sentence is used merely for emphasis, it is expressed by repeating the negative no.
I didn't do it, either!
¡No lo he hecho, no!
100. Neither is ni as a conjunction and equal to and ... either. As a pronoun it is ni el uno ni el otro. Standing as the first word in a sentence neither is translated tampoco.
I do not look into the mirror, neither to-day nor ever.
No miro en el espejo, ni hoy ni nunca.—ECHEGARAY.
He wouldn't help him, neither would he help me.
No quería ayudarle a él, tampoco quería ayudarme a mí.
I showed him the drawings. Neither of them pleased him.