Fix "polyfills" typo

Author: odsantos

1-js/03-code-quality/06-polyfills/article.md

@@ -78,7 +78,7 @@ Two interesting libraries of polyfills are:
 
 ## Summary
 
-In this chapter we'd like to motivate you to study modern and even "bleeding-edge" langauge features, even if they aren't yet well-supported by JavaScript engines.
+In this chapter we'd like to motivate you to study modern and even "bleeding-edge" language features, even if they aren't yet well-supported by JavaScript engines.
 
 Just don't forget to use transpiler (if using modern syntax or operators) and polyfills (to add functions that may be missing). And they'll ensure that the code works.