Does a restrictive word phrase or clause always limit the meaning of the word just before it?

Question

Non-restrictive

(of a relative clause or descriptive phrase) giving additional information about a noun phrase whose particular reference has already been specified.

I read that a restrictive word phrase or clause "limits" meaning, because it is not inessential. I get this. Is that "limit" always of the meaning of the word just before it, never a word before that or after itself?

An example of it doing so would be the following:

My sister Susan went to the shop.

'Susan' limits the meaning of my 'sister', because I am expressing that it is not just any sister, but Susan. The non restrictive version would be:

My sister, Susan, went to the shop.

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Two follow on questions:

1. Can every restrictive word phrase and clause be made non-restrictive by the addition of a parenthetical comma, and vice versa by deleting parentheses.

2. And is every parenthetical element non restrictive?

Answer 1

I am not too certain of what you mean by "limit the meaning of the word just before," but here is the answer to my interpretation of what I believe you are asking:

Making a clause non-restrictive by setting it off with commas makes it so that the clause can be removed without altering the meaning of the sentence; and, conversely, the meaning of the word just before is limited in its meaning to serve the purpose of any restrictive element that may follow it.

In your example "My sister, Susan, went to the shop," because "Susan" is set off by commas, rendering it non-restrictive, it follows that your sentence is equivalent to "My sister went to the shop." Therefore, if you set off "Susan" with a pair of commas, you are implying that you only have ONE sister.

Contrarily, the sentence "My sister Susan went to the shop" does not impose the condition of you necessarily having only one sister. So you may then say, "My sister Susan went to the shop, and my sister Mary stayed home" because making the names restrictive clauses implies that you may have more than one sister.

If you have exactly one sister, it is more common to employ a non-restrictive clause, but if you have more than one, then you MUST employ a restrictive clause.

So long as the sentence makes sense and is grammatical, feel free to use parentheticals to set off clauses, though any and all parentheticals are non-restrictive.