Breakdown of Я уменьшаю яркость экрана вечером, чтобы легче засыпать.
я
I
вечером
in the evening
чтобы
so that
экран
the screen
Questions & Answers about Я уменьшаю яркость экрана вечером, чтобы легче засыпать.
Why is the verb уменьшаю in the imperfective, and what would change if I used уменьшу?
Уменьшаю is the 1st person singular present of the imperfective verb уменьшать. It suggests a habitual/repeated action: you do this (regularly) in the evenings.
If you use уменьшу (perfective уменьшить), it points to a single completed action (often with a future meaning): Я уменьшу яркость экрана вечером... = I will reduce the screen brightness in the evening (at some point), in order to....
How do I know that уменьшаю means I reduce / I am reducing?
Russian present-tense forms of imperfective verbs cover both English I reduce (habit) and I am reducing (in progress). Context decides. Here вечером strongly pushes the habitual reading: I reduce it in the evening(s)..
Why is there no word for I like я—oh wait, there is Я. Could it be omitted?
Yes, Russian can omit the subject pronoun because the verb ending already shows the person/number (-аю = 1st person singular).
So Уменьшаю яркость экрана вечером... is natural in context. Keeping Я adds emphasis/contrast (for example, I do this (not someone else)).
What case is яркость, and why?