In PHP (and many other languages), there are certain characters that are considered special.
These special characters are typically used for language syntax. Common examples include quotation marks, semicolons, etc.
In order to use these characters in on-screen text (like this), the developer must escape the characters using a backslash before the character.

This is an example of using an escape slash:
John said, "What time is it"
Enrique replied, "05:09 AM".

This is an example of NOT using an escape slash:
John said, What time will we meet tomorrow?
Enrique replied, 05:09 AM.