diff --git a/include/libpsl.h b/include/libpsl.h
index 4ead03d..39a5017 100644
--- a/include/libpsl.h
+++ b/include/libpsl.h
@@ -74,13 +74,13 @@ psl_ctx_t *
 /* retrieves builtin PSL data */
 const psl_ctx_t *
 	psl_builtin(void);
-/* checks wether domain is a public suffix or not */
+/* checks whether domain is a public suffix or not */
 int
 	psl_is_public_suffix(const psl_ctx_t *psl, const char *domain);
-/* checks wether cookie_domain is acceptable for domain or not */
+/* checks whether cookie_domain is acceptable for domain or not */
 int
 	psl_is_cookie_domain_acceptable(const psl_ctx_t *psl, const char *hostname, const char *cookie_domain);
-/* returns the longest unregistrable domain within 'domain' or NULL if none found */
+/* returns the longest not registrable domain within 'domain' or NULL if none found */
 const char *
 	psl_unregistrable_domain(const psl_ctx_t *psl, const char *domain);
 /* returns the shortest possible registrable domain part or NULL if domain is not registrable at all */