The Present Indicative - Irregular Verbs.

In the study of Spanish, one of the most significant challenges is the conjugation of irregular verbs in the present indicative. Here are some of the most common types of irregularities:

Verbs with changes in the first person: Some verbs have unique forms in the first person singular, different from other regular conjugations. Examples include:

• “Hacer” is conjugated as “hago”.

• “Salir” is conjugated as “salgo”.

• “Tener” is conjugated as “tengo”.
  

Verbs with a vowel change in the root: Many irregular verbs experience a change in the vowel of their root when conjugated in some forms. The most common changes are:

• E > IE: As in “cerrar,” which is conjugated as “cierro”, “cierras”, “cierra”.

• O > UE: As in “dormir,” which is conjugated as “duermo”, “duermes”, “duerme”.

• E > I: As in “servir,” which is conjugated as “sirvo”, “sirves”, “sirve”.

• U > UE: As in “jugar,” which is conjugated as “juego”, “juegas”, “juega”.
  

Verbs ending in -UIR: These verbs usually add a ‘y’ in some forms. Examples include:

• “Construir” is conjugated as “construyo”, “construyes”, “construye”.
  

Verbs with two types of irregularities: Some verbs present more than one irregularity, which requires special attention. For example:

• “Tener” changes the root (“tien-” in some forms) and has an irregular ending in the first person (“tengo”).
  

Completely irregular verbs: These verbs do not follow common patterns and their conjugations must be memorised. Classic examples are:

• Ir se conjuga como “voy”, “vas”, “va”, “vamos”, “vais”, “van”.

• Ser se conjuga como “soy”, “eres”, “es”, “somos”, “sois”, “son”.

• Oír se conjuga como “oigo”, “oyes”, “oye”, “oímos”, “oís”, “oyen”.
  

Table with Some of the Most Common Irregular Verbs in Present Indicative:

Verbo (Español)	Primera Persona Singular (Yo)	Raíz	Significado (Inglés)
ser	soy	s-, e-	to be (essential)
estar	estoy	est-	to be (state)
ir	voy	v-	to go
tener	tengo	tien-, ten-	to have
venir	vengo	vien-, ven-	to come
hacer	hago	hac-	to do, to make
poder	puedo	pued-, pod-	to be able to, can
poner	pongo	pon-	to put, to place
saber	sé	sab-	to know (facts)
decir	digo	dic-, dec-	to say, to tell
dar	doy	d-	to give
ver	veo	v-	to see
salir	salgo	sal-	to leave, to go out
traer	traigo	tra-	to bring
valer	valgo	val-	to be worth
caber	quepo	cab-	to fit
andar	ando	and-	to walk
conocer	conozco	conoc-	to know (people), to meet
conducir	conduzco	conduc-	to drive
traducir	traduzco	traduc-	to translate
producir	produzco	produc-	to produce
construir	construyo	construy-, constru-	to build
seguir	sigo	sigu-	to follow, to continue
oír	oigo	oy-, o-	to hear
dormir	duermo	duerm-, dorm-	to sleep
pedir	pido	pid-, ped-	to ask for, to request
sentir	siento	sient-, sent-	to feel
morir	muero	muer-, mor-	to die
elegir	elijo	elig-	to choose
reír	río	rí-	to laugh

Here I leave you a link to a verb conjugator that will be very helpful when you need to conjugate a verb.

https://www.elconjugador.com/esindex.php