...so is applicable to all environments - Where did the subject of the verb go?

Question

This book is about JavaScript and focuses on its object-oriented nature. The book starts from zero, and does not assume any prior programming knowledge. Although there is one chapter dedicated to the web browser environment, the rest of the book is about JavaScript in general, so is applicable to all environments.

What is applicable to all environments? Where did the subject of the verb go?

Answer 1

1. Basic Answer.

The original author left out the subject, so you need to figure it out from context.¹ As others noted, we can supply "a subject" by adding the word "it":

• "Although there is one chapter dedicated to the web browser environment, the rest of the book is about JavaScript in general, so it is applicable to all environments.

But that still doesn't answer, what is it? It's easier if you consider the same sentence based on a hypothetical book called How to Drive a Car:

• Although there is one chapter dedicated to the Honda Civic stick-shift, the rest of the book is about driving in general, so ________________________ is applicable to driving any car.
  Answer: it | this book | the rest of the book.

So the answer is the same:

• Although there is one chapter dedicated to the web browser environment, the rest of the book is about JavaScript in general, so ________________________ is applicable to all JavaScript environments.
  Answer: it | this book | the rest of the book.

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2. More Detail - Understanding Sentence Structure

The key to answering this question is understanding "what the sentence saying". And that requires both (1) understanding the semantics of the sentence structure and (2) world-knowledge about JavaScript.² Let's start with the semantics of the sentence structure:

• Although X, Y, so Z"

• Although something-is-true, some-contrasting-thing-is-true, so/therefore some-conclusion-is-made.

• Although Joe was fast, Jim was faster, so/therefore ______________ won the race.
  Answer: Jim. Because we know that "faster people wins races".

• Although the building has pipes, they aren't working, so/therefore ______________ need to be fixed.
  Answer: they | the pipes. Because we know that "broken pipes need to be fixed".

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3. More Detail - When can subjects be dropped?

Subjects can be dropped in a variety of ways. The following shows how the original sentence can be reworded with a more grammatical parallel structure so that the subject, "this book", is clearly shared across all three clauses:

• This book has only one chapter dedicated to the web browser environment, is about JavaScript in general, and therefore is applicable to all environments.

The above is just one example of a compound sentence with parallel structures.³

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Footnotes

^{1. As noted in the following link, the author, a non-native English speaker, has some difficulty with English: See https://ell.stackexchange.com/a/26899/3796. The phrase "so is applicable" might be used where there is less chance for ambiguity (see Google Ngram). But leaving out the subject in this sentence verges between being poor style at best and being ungrammatical at worst.}

^{2. Here's some info about JavaScript. JavaScript is a general purpose scripting language that most notably runs in web-browsers, but also runs in other environments like servers, batch programs, desktop programs, and in applications. While many JavaScript books focus on the web-browser environment, programmers working in other environments will appreciate a book that focuses more on the language instead of any particular environment.}

^{3. More specifically, as per @snailplane's comment, this is an example of verb phrase coordination. An even simpler example of this is, "He sings and dances." (He sings and he dances.)}

Answer 2

The subject of the verb is 'the rest of the book'. We could say 'the rest of the book is about JavaScript in general, so it is applicable ...'. English sometimes drops some words if they are understood (or understandable) from the rest of the sentence. Maybe if this sentence was written for English language learners, the writer would have included the word 'it', but I think it was written for native or advanced non-native speakers. I probably would have included it anyway.

Answer 3

I'll first reiterate what the other answers said before I go into a bit more detail. The sentence is correctly read as:

Although there is one chapter dedicated to the web browser environment, the rest of the book is about JavaScript in general, so it is applicable to all environments.

This is because so here is a coordinating conjunction^[1][2] and thus must be followed by an independent clause, which must contain a subject and verb. Since "is applicable to all environments" is not an independent clause, this sentence is incorrect. (Even though we can understand what it means.)

Both @CoolHandLouis and @SydneyAustraliaESLTeacher alluded to the fact that it was dropped either unknowingly or in an attempt to be colloquial, and I suspect this is the case as well. However, not only does it still remain ungrammatical, there is something to keep in mind...

The words so and therefore are often used interchangeably; however this is not always grammatical. The word therefore would actually be an adverb here, which need not be followed by an independent clause. It could read as follows:

Although there is one chapter dedicated to the web browser environment, the rest of the book is about JavaScript in general, and therefore is applicable to all environments.

Because an adverb here can be followed by either a dependent or independent clause, the use of it is optional here. As for the example you showed, however, so followed by a subject-less clause is incorrect, and thus it is required to be grammatical.

Answer 4

Every language has rules about what words must be included in a particular context, what words are usually included but can be left out, what words are usually left out but can be included, and what words must be left out. Some of these are common and widespread enough that they are specifically taught at language learner level. Others are rare and/or only used in particular contexts.

In the OP’s sentence, it is certainly more usually to include the subject (‘it’) of the second clause, but the rules of English allow it to be left out. Why? Basically because English speakers across the centuries accepted that it could.

When elements (words, phrases, clauses) of English are ‘coordinated‘ (joined by ‘and’, ‘or‘ or ‘but’) some elements of meaning carry over and can be replaced by ‘anaphora’ (‘referring back’) or can be omitted. To take a simpler example:

My best friend is beautiful and my best friend is popular.

becomes:

My best friend is beautiful and she is popular. (less natural)

or:

My best friend is beautiful and popular. (more natural)

‘So’ is a subordinating conjunction, which complicates things:

My best friend is beautiful, so she is popular.

may become:

(?) My best friend is beautiful, so is popular.

‘and so’ uncomfortably combines the coordinating conjunction ‘and’ and the subordinating conjunction ‘so’:

My best friend is beautiful, and so she is popular. > (?) My best friend is beautiful, and so is popular.

which is the same general structure as OP’s sentence (among many differences, of course).

[EDIT: I've just re-read OP's sentence and realised that there's no 'and' in the middle of it.

Answer 5

What is applicable to all environments? Where did the subject of the verb go?

• The rest of the book is applicable in all environments.
• The subject is rest of the book and it didn't go anywhere and it's perfectly OK right where it is. Were you expecting a pronoun; i.e. "it?" (to be applicable in all environments?) No, no pronoun is necessary and this paragraph makes for an easy read.

A good ESL teacher will come up with drills and situations to help you use and understand this structure with ease.

Answer 6

The rest of the book is about JavaScript in general and it is applicable to all environments (web browser, and not)