Index: lldb/include/lldb/Interpreter/CommandCompletions.h
===================================================================
--- lldb/include/lldb/Interpreter/CommandCompletions.h
+++ lldb/include/lldb/Interpreter/CommandCompletions.h
@@ -45,10 +45,11 @@
     eModuleUUIDCompletion = (1u << 17),
     eStopHookIDCompletion = (1u << 18),
     eTypeCategoryNameCompletion = (1u << 19),
+    eTypeLanguageCompletion = (1u << 20),
     // This item serves two purposes.  It is the last element in the enum, so
     // you can add custom enums starting from here in your Option class. Also
     // if you & in this bit the base code will not process the option.
-    eCustomCompletion = (1u << 20)
+    eCustomCompletion = (1u << 21)
   };
 
   static bool InvokeCommonCompletionCallbacks(
@@ -128,6 +129,9 @@
   static void TypeCategoryNames(CommandInterpreter &interpreter,
                                 CompletionRequest &request,
                                 SearchFilter *searcher);
+
+  static void TypeLanguages(CommandInterpreter &interpreter,
+                            CompletionRequest &request, SearchFilter *searcher);
 };
 
 } // namespace lldb_private
Index: lldb/source/Commands/CommandCompletions.cpp
===================================================================
--- lldb/source/Commands/CommandCompletions.cpp
+++ lldb/source/Commands/CommandCompletions.cpp
@@ -20,6 +20,7 @@
 #include "lldb/Interpreter/OptionValueProperties.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/Variable.h"
+#include "lldb/Target/Language.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/RegisterContext.h"
 #include "lldb/Target/Thread.h"
@@ -71,6 +72,7 @@
       {eWatchPointIDCompletion, CommandCompletions::WatchPointIDs},
       {eStopHookIDCompletion, CommandCompletions::StopHookIDs},
       {eTypeCategoryNameCompletion, CommandCompletions::TypeCategoryNames},
+      {eTypeLanguageCompletion, CommandCompletions::TypeLanguages},
       {eNoCompletion, nullptr} // This one has to be last in the list.
   };
 
@@ -741,3 +743,13 @@
         return true;
       });
 }
+
+void CommandCompletions::TypeLanguages(CommandInterpreter &interpreter,
+                                       CompletionRequest &request,
+                                       SearchFilter *searcher) {
+  for (int bit :
+       Language::GetLanguagesSupportingTypeSystems().bitvector.set_bits()) {
+    request.TryCompleteCurrentArg(
+        Language::GetNameForLanguageType(static_cast<lldb::LanguageType>(bit)));
+  }
+}
Index: lldb/source/Interpreter/CommandObject.cpp
===================================================================
--- lldb/source/Interpreter/CommandObject.cpp
+++ lldb/source/Interpreter/CommandObject.cpp
@@ -1062,7 +1062,7 @@
     { eArgTypeGDBFormat, "gdb-format", CommandCompletions::eNoCompletion, { GDBFormatHelpTextCallback, true }, nullptr },
     { eArgTypeHelpText, "help-text", CommandCompletions::eNoCompletion, { nullptr, false }, "Text to be used as help for some other entity in LLDB" },
     { eArgTypeIndex, "index", CommandCompletions::eNoCompletion, { nullptr, false }, "An index into a list." },
-    { eArgTypeLanguage, "source-language", CommandCompletions::eNoCompletion, { LanguageTypeHelpTextCallback, true }, nullptr },
+    { eArgTypeLanguage, "source-language", CommandCompletions::eTypeLanguageCompletion, { LanguageTypeHelpTextCallback, true }, nullptr },
     { eArgTypeLineNum, "linenum", CommandCompletions::eNoCompletion, { nullptr, false }, "Line number in a source file." },
     { eArgTypeLogCategory, "log-category", CommandCompletions::eNoCompletion, { nullptr, false }, "The name of a category within a log channel, e.g. all (try \"log list\" to see a list of all channels and their categories." },
     { eArgTypeLogChannel, "log-channel", CommandCompletions::eNoCompletion, { nullptr, false }, "The name of a log channel, e.g. process.gdb-remote (try \"log list\" to see a list of all channels and their categories)." },
Index: lldb/test/API/functionalities/completion/TestCompletion.py
===================================================================
--- lldb/test/API/functionalities/completion/TestCompletion.py
+++ lldb/test/API/functionalities/completion/TestCompletion.py
@@ -426,6 +426,9 @@
             self.complete_from_to('type category ' + subcommand + ' ', ['default'])
         self.complete_from_to('type filter add -w ', ['default'])
 
+    def test_common_completion_type_language(self):
+        self.complete_from_to('type category -l ', ['c'])
+
     def test_command_argument_completion(self):
         """Test completion of command arguments"""
         self.complete_from_to("watchpoint set variable -", ["-w", "-s"])