Adverb clauses or phrases are essential or non-essential depending on the context or a comma?

Question

According to many guides online, non-essential adverb clauses or adverb phrases are by commas.

However, I have found that no matter whether they are separated or not, adverb clauses and phrases seems to be essential or non-essential depending on the context or the interpretation.

Example 1

I like to hang out with my friends, in the arcade.

I like to hang out with my friends in the arcade.

The adverb phrases above are actually both essential in my opinion because they specify the place. Both of the sentences mean the same: I like to hang out with my friends in the arcade and maybe I don't enjoy it at another place.

Example 2

I didn't talk to Emily, when we were in the math class yesterday.

I didn't talk to Emily when we were in the math class yesterday.

The adverb clauses are actually both essential in my opinion because it specifies a time. Both of the sentences mean the same: I didn't to talk to Emily in the math class yesterday. However, maybe we talked afterward.

Example 3

I never walk past this street, because I am afraid of the stray dogs.

I never walk past this street because I am afraid of the stray dogs.

The adverb clauses are both non-essential in my opinion. They don't change the fact that I never walk past the street. Both of the sentences mean the same: I never walk past this street.

Answer 1

You have got the whole thing backwards.

Commas do not determine grammar. Grammar determines proper use of commas.

In example 1, the comma is wrong because the clause is essential and follows the independent clause

In example 2, the comma is wrong because the clause is essential and follows the independent clause.

In example 3, the comma is wrong because the clause is essential and follows the independent clause.

If, however, you reverse the order of the dependent and independent clauses, they should be separated by a comma.

Answer 2

When an adverbial phrase follows the verb that it modifies, it is usually considered essential. Thus, the sentences with commas in your first two examples are unusual; you wouldn't normally see them in standard English.

However, such adverbial phrases can sometimes be nonessential, so commas can make a difference. Consider the following:

You speak Spanish, as Mexicans do!

This means that you speak Spanish and Mexicans speak Spanish; the two ideas are not closely related.

You speak Spanish as Mexicans do!

This means that you speak Spanish in the same way as Mexicans (and presumably not in the same way as Spaniards, Peruvians, etc.).

The adverbial clause in your third example can also be considered either essential or nonessential:

I never walk past this street, because I am afraid of the stray dogs.

This sentence indicates that the speaker never walks past this street. It also provides the reason.

I never walk past this street because I am afraid of the stray dogs.

This sentence answers the question, "Do you ever walk past this street because you are afraid of the stray dogs?" The speaker responds in the negative; however, the speaker might walk past this street for other reasons.

The difference between essential and nonessential phrases can be pretty subtle; native speakers frequently disagree about the issue and often simply get it wrong. Nevertheless, there is a difference.