refactor(lang): frappe.translate.get_language

User.language should be given higher priority in terms of
authenticated user since they chose it. Even higher than the
browser they're using...even if the system locales aren't set
properly and browser isn't configured properly

frappe/auth.py

@@ -154,7 +154,6 @@ class LoginManager:
 		self.make_session()
 		self.setup_boot_cache()
 		self.set_user_info()
-		self.clear_preferred_language()
 
 	def get_user_info(self):
 		self.info = frappe.db.get_value("User", self.user,

frappe/translate.py

@@ -27,11 +27,12 @@ def get_language(lang_list: List = None) -> str:
 
 	Order of priority for setting language:
 	1. Form Dict => _lang
-	2. Cookie => preferred_language
-	3. Request Header => Accept-Language
+	2. Cookie => preferred_language (Non authorized user)
+	3. Request Header => Accept-Language (Non authorized user)
 	4. User document => language
 	5. System Settings => language
 	"""
+	is_logged_in = frappe.session.user != "Guest"
 
 	# fetch language from form_dict
 	if frappe.form_dict._lang:
@@ -41,6 +42,10 @@ def get_language(lang_list: List = None) -> str:
 		if language:
 			return language
 
+	# use language set in User or System Settings if user is logged in
+	if is_logged_in:
+		return frappe.local.lang
+
 	lang_set = set(lang_list or get_all_languages() or [])
 
 	# fetch language from cookie