Stem change patterns
end with *cer preceded by a vowel ( conocer )
end with *ucir ( conducir )
end with *cer or *cir preceded by a consonant ( convencer )
end with *ger or *gir ( coger, fingir )
end with *aer ( caer )
end with *guir ( seguir )
end with *uir not preceded by a g ( incluir )
*cer after a vowel and *ucir
_____ ( conocer )
_____ ( nacer )
_____ ( conducir )
_____ ( producir )
Irregular in the yo form only
Formula: z added before c
conozco
nazco
conduzco
produzco
*cer after a consonant
*cir after a consonant
_____ ( convencer )
_____ ( ejercer )
_____ ( esparcir )
Irregular in the yo form only
Formula: z replaces c
convenzo
ejerzo
esparzo
*ger or *gir
_____ ( coger )
_____ ( recoger )
_____ ( exigir )
_____ ( fingir )
Irregular in the yo form only
Formula: j replaces g
cojo
recojo
exijo
finjo
*aer
_____ ( atraer )
_____ ( caer )
_____ ( traer )
Irregular in the yo form only
Formula: ig added to a
atraigo
caigo
traigo
*guir
_____ ( distinguir )
_____ ( erguir )
_____ ( seguir )
Irregular in the yo form only
Formula: u removed
distingo
irgo
sigo
erguir is tricky, because it changes e to i, and also that i applies to the boot
*uir except *guir
yo _____ ( concluir )
yo _____ ( destruir )
yo _____ ( incluir )
This pattern affects the whole boot
Formula: y added to stem
concluyo
destruyo
incluyo