Questions & Answers about Если не смогу дозвониться до тебя вечером, напишу в чат.
Russian often drops personal pronouns when the verb ending already makes the subject clear.
- смогу = I will be able
- напишу = I will write
So я is understood automatically. You can say Если я не смогу..., but it usually sounds more emphatic, as if you are contrasting I with someone else.
Смогу means I will be able.
It is the 1st person singular future form used with мочь / смочь. In this sentence, it works like a modal verb:
- не смогу дозвониться = I won’t be able to get through by phone
So the structure is:
- смогу = will be able
- дозвониться = to get through by phone