Questions & Answers about Я жду письма от него.
Why is it жду and not ждать in this sentence?
Because Russian verbs have to be conjugated to match the subject.
- ждать is the infinitive: to wait.
- жду is the 1st person singular present form: I wait / I am waiting.
So:
- Я жду = I wait / I am waiting
- Ты ждёшь = You wait / you are waiting
- Он/она ждёт = He/she waits / is waiting, etc.
Using the infinitive ждать here (Я ждать письма...) would be ungrammatical unless it were part of a different construction (e.g., Я буду ждать письма – I will wait for the letter).
Why is it письма here and not the dictionary form письмо?
The dictionary form письмо is nominative singular (the form you look up).
In Я жду письма от него, the noun письмо is changed to письма because it is in the genitive singular case, required by the verb ждать in this context.
Basic forms of письмо:
- Nominative singular: письмо – a letter (subject)
- Genitive singular: письма – of a letter / a letter (as object with certain verbs)
- Nominative plural: письма – letters
- Genitive plural: писем – of letters