"I am already eating."
Translation:Я уже ем.
You cannot say "я уже ест", it does not make sense. It would be like saying "I already eats".
I am already eating - я уже ем
You are already eating - ты уже ешь
He is already eating - он уже ест
She is already eating - она уже ест
We already eat - мы уже едим
You are already eating - вы уже едите
They are already eating - они уже едят
я ем (ем только от первого лица=first person only)
"ест" - (указывая на кого-то; pointing to someone) он ест она ест кто-то ест (somebody)
(если говорить про =if we talk about) (домашнее животное = pet) it’s not called “it” it's called only by gender: "he", "she" as a person
Ем is talking about yourself i believe and ест is when your refering to someone else
Yes, the sentence would sound unnatural without «я».
Some Slavic sentences (like Slovenian) allow dropping the pronouns, others (like Russian and Ukrainian) allow dropping the verb 'to be'. These two traits usually don't go well together.
Although in the Present tense you can safely understand «ем» means «я ем», in the Past tense this becomes a problem. In Slovenian, you can drop «jaz» in «jaz hotel sem» and still understand what «hotel sem» means. In Russian, «я хотел» has already dropped the verb 'to be' (if you say 'я есмь хотел' people would think you're speaking Church Slavonic or something, but definitely not Russian), so if you drop «я», just the word «хотел» is not enough to understand it's 1st person verb
So, some languages allow dropping pronouns, and some allow dropping the verb 'to be', but not both. Russian allows dropping the verb 'to be', so it's much more strict with the pronouns.