My level of Japanese is still very basic. So sorry if I what I'm saying doesn't make sense.
As I understand it, Japanese do not like the usage of pronouns to express if a sentence's subject or direct object is in the 1st, 2nd or 3rd person. Actually Japanese seems to use as little pronouns as possible. But even when replacing pronouns by people's name the subject tends to be completely dropped.
The reasoning given by most learning resources online is that you should get it from the context and that you will learn to understand if after hundred of hours of immersion. But based on the little immersion I could do, on example sentences from ejje.weblio and other learning resources explaining grammar point by point, I think (hopefully I'm not completely wrong) there is more to that. And even completely out of context, a sentence can contains enough information to tell what the subject is without relying on pronouns.
Here's a few sentences and what, I, as a beginner listener would assume the subject to be.
悲しそうだよね。
I would assume that the subject would be "you", based on the usage of "そう" and the particule "よね".
悲しいの?
I would assume that the subject is "you", because it's a question.
悲しいよ。
I would assume that the subject is "I", because of the particle "よ"
悲しがってるとおもう。
I would assume that the subject is "he/she", based on the usage of the verb がる and the ending in "とおもう"
First of all, are my assumptions correct? If I'm right, my question would be the following:
Do you know any other example of words or expression that can help understand if the subject is 1st, 2nd or 3rd person without using pronouns? I think I would understand enough to read or listen to this kind of sentences, but it would help me to express myself better if I knew all those little words and expressions.
Edit:
I just thought of another one: ほしい is automatically "I want" and can't be use for "you want" or "he/she wants".
Edit 2:
I replaced 怖い by 悲しい as it seems more suitable for my examples. I wanted examples that implies that the subject is a person.
Also the end goal here is not just better understanding, because, yes context DOES matter. The end goal here is how can I express myself better. I want to drop the 私は あなたは 田中せんは etc. but still be able to be understood. Like when should I use ほしい and not -たい, when should I use がる, am I clear enough or should I add a subject for this sentence? This kind of stuff. If I understand the implications of those little words better it would help me to know when the topic/subject is absolutely necessary and when I can drop it.