An array is a list of items. a string is marked by the quotation marks. this array contains a list of strings, so a list of items that are marked by content encapsulated by quotation marks. The quotation marks are not literally part of the content of the string.
for instance I could store a string in a variable
var str = "this is a string";
but when i choose to log this to the console
console.log(str);
it would not actually output the quotation marks, and the result would be:
this is a string
EDIT:
if what you need is an actual string that looks like
[word1, word2, word3, word4]
you can take every single string in the array, and join them with eachother. then you put the brackets behind and in front and you would get that as an output.
example:
var arr = ["word1", "word2", "word3", "word4"];
var joinedstring = "[" + arr.join(', ') + "]";