Breakdown of Мой друг обещал прийти в гости сегодня.
друг
friend
мой
my (мой, моя, моё) / mine
в
in / to (direction)
гость
guest
Questions & Answers about Мой друг обещал прийти в гости сегодня.
Why do we use прийти here instead of just идти?
Идти just means "to go" or "to walk," but the prefix при- adds the meaning of arrival. So, прийти specifically means to arrive on foot, or it acts as the general word for "to come over."
Could I use приехать instead of прийти in this sentence?
Yes! If your friend lives far away and is driving or taking transit to your place, you would use приехать (to arrive by transport). Прийти implies they are walking, or it is used as a general default when the exact transport does not matter.
How does в гости translate to "visit"?
The word гость means "guest," and the set phrase в гости literally translates to "into guests." In Russian, you usually do not use a verb for "to visit" a person; instead, you go "into guests." Because it shows your destination, гости is in the accusative case here.
Why does прийти have a й when the base verb идти does not?
When the prefix при- is added to идти, the spelling changes slightly. The и turns into й, making the perfective verb прийти. Remember that its imperfective partner is completely different: приходить.