Subject confusion in ~たい sentences

Question

I know たい means "want to." But the examples below confused me. Especially the second sentence translates to "I want to eat." I don't know why this is the translation. I'm not sure what is the subject in the second sentence. If I use "I", then it would be awkward because it would mean "I am want-to-eatable"? Is it a weird exception? If the actual subject is "I", I'm not sure why would たい mean "want to eat" instead of "want-to-eatable."

僕は魚が食べたい。

lit: As for me, fish is want-to-eatable.

僕は食べたい。

lit: As for me, [SUBJECT] is want-to-eatable.

Answer 1

In a clause, both the subject and the object for 食べたい are marked with が. In other words, "(that) I want to eat fish" is expressed as 私が 魚が 食べたい（こと）.

In a sentence, however, you have to add は to either or both of the subject and the object. When you add it to the subject, the sentence becomes 私は 魚が 食べたい. Likewise, 魚は 私が 食べたい for object, and 私は 魚は 食べたい for both.