>コーヒーはテーブルにあります does not tell you if coffee is on the table or near the table or on the tray. and we have to convert same ambiguity into English
I don't think this particular sentence is ambiguous at all. If someone was going to say something was near the table, they would say something like コーヒーはテーブルのそばにあります or maybe even コーヒーはテーブルの近くにあります. If the coffee is on a tray on the table, then even in English you could say "the coffee is on the table" and I don't think anyone could argue that it's ambiguous unless they are a lawyer maybe.
>while if I say "watashi de" it is obvious that it translates to "in me"
Can you show an example sentence where you would say "watashi de" that translates to "in me"? I can think of a few examples where I can say "watashi de" (such as watashi de yokereba), but they don't mean anything near "in me".
Anyway, don't worry about how exactly it translates into English. As long as you get a general enough sense of how the grammar is interacting with the sentence then that's enough. Read a lot of example sentences, practice using it yourself and have natives correct your sentences, internalize the grammar and understand how it works, and then you'll be able to come up with a good translation for sentences. If you think English "at" or "in" every time you see で or に or whatever then you're probably just not at that stage yet, which isn't a bad thing, but it says you need to study more.
I don't think this particular sentence is ambiguous at all. If someone was going to say something was near the table, they would say something like コーヒーはテーブルのそばにあります or maybe even コーヒーはテーブルの近くにあります. If the coffee is on a tray on the table, then even in English you could say "the coffee is on the table" and I don't think anyone could argue that it's ambiguous unless they are a lawyer maybe.
>while if I say "watashi de" it is obvious that it translates to "in me"
Can you show an example sentence where you would say "watashi de" that translates to "in me"? I can think of a few examples where I can say "watashi de" (such as watashi de yokereba), but they don't mean anything near "in me".
Anyway, don't worry about how exactly it translates into English. As long as you get a general enough sense of how the grammar is interacting with the sentence then that's enough. Read a lot of example sentences, practice using it yourself and have natives correct your sentences, internalize the grammar and understand how it works, and then you'll be able to come up with a good translation for sentences. If you think English "at" or "in" every time you see で or に or whatever then you're probably just not at that stage yet, which isn't a bad thing, but it says you need to study more.
Edited: 2016-02-08, 12:06 pm

