diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index fea2d871..05ba1cd4 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -809,6 +809,7 @@ Erlang:
   - .es
   - .escript
   - .hrl
+  ace_mode: erlang
 
 F#:
   type: programming
@@ -894,6 +895,7 @@ Forth:
   - .for
   - .forth
   - .frt
+  ace_mode: forth
 
 Frege:
   type: programming