[MUSIC]
Okay, we've seen many verbs now in the present tense which are regular.
But now we're going to see some irregular ones in the present tense,
because their stem vowel splits into two parts.
They call that a dipthong.
When they receive stress on this vowel, the vowel splits in to two parts.
So, there are only two vowels that we're talking about.
One ends in E and it changes to IE.
And the other is O and it changes to UE.
Now the nosotros and vosotros forms are unaffected by these changes because
the root vowels are never stressed in the present tense.
So let's look at some examples.
If we take a verb that is an ar verb like empezar,
which means to begin or to start.
Whenever the stress falls on the e, it's going to split into two parts.
And if it doesn't, it'll just be the same.
So let's look at the first form yo empiezo,
tu empiezas, el empieza, nosotros empezamos,
vosotros empezáis, and ellos empiezan.
For an or an ir verb, like for instance poder, to be able to.
Very useful verb, work a little bit with this verb poder
because we repeat it over and over and over again.