I instant-messaged this to a friend last week.

Problem:
The statement is ambiguous without a hyphen.

Explanation:
What does “Face time matters.” mean to you?

Soon after I instant-messaged this statement, I realized that my friend could interpret what I wrote in two ways.

One interpretation of the statement is that I was commanding or imploring my friend to seriously consider “time matters”.

In other words, one interpretation of “Face time matters.” is that this was an imperative statement.

The other interpretation of “Face time matters.” is that I was telling my friend that “face time” with other people makes a difference.

These two interpretations are possible because the word “face” is both a noun and a verb and because the word “matters” is both a noun and a verb.

The solution comes from using a hyphen to indicate whether one is talking about about “time matters” or about “face time”.

Written schematically, what we have is [NOUN|VERB] NOUN [VERB|NOUN], and any sentence that follows this pattern will be ambiguous without a hyphen between the first and second words or between the second and third words.

Some might argue that using an exclamation mark instead of a period in “Face time matters.” would make it clear to the reader that the statement is an imperative.

Unlike Spanish, which tends to favor the use of exclamation marks for imperative statements, American English seems to have dropped the common use of exclamation marks for imperatives a long time ago.

Using a period instead of an exclamation mark at the end of an imperative statement is consistent with my “Devolution toward Simpler” linguistic hypothesis. It is simpler to write a period than it is to write an exclamation mark (one stroke versus two strokes). And it is simpler to type a period than it is to type an exclamation mark (one key versus two keys).

So the absence of the exclamation mark does not assure American readers that the statement is not an imperative.

But I would counter-argue that the presence an exclamation mark at the end of a sentence with this pattern does not ensure that the sentence will be interpreted as imperative. Instead, the exclamation mark could be interpreted as turning a declarative statement into an exclamatory statement.

Solution:

• Use “Face time-matters.” — with a hyphen between “time” and “matters” — to ensure that the statement is interpreted as an imperative sentence about facing matters of time.
• Use “Face-time matters.” — with a hyphen between “Face” and “time” — to ensure that the statement is interpreted as a declarative sentence about the importance of spending face-to-face time with others.