diff --git a/spec/integration/compile_grammar_spec.cc b/spec/integration/compile_grammar_spec.cc
index 14d026d0..743ea286 100644
--- a/spec/integration/compile_grammar_spec.cc
+++ b/spec/integration/compile_grammar_spec.cc
@@ -513,9 +513,9 @@ describe("compile_grammar", []() {
         "name": "external_scanner_example",
 
         "externals": [
-          "percent_string",
-          "percent_string_start",
-          "percent_string_end"
+          "_percent_string",
+          "_percent_string_start",
+          "_percent_string_end"
         ],
 
         "extras": [
@@ -548,13 +548,13 @@ describe("compile_grammar", []() {
           "string": {
             "type": "CHOICE",
             "members": [
-              {"type": "SYMBOL", "name": "percent_string"},
+              {"type": "SYMBOL", "name": "_percent_string"},
               {
                 "type": "SEQ",
                 "members": [
-                  {"type": "SYMBOL", "name": "percent_string_start"},
+                  {"type": "SYMBOL", "name": "_percent_string_start"},
                   {"type": "SYMBOL", "name": "expression"},
-                  {"type": "SYMBOL", "name": "percent_string_end"}
+                  {"type": "SYMBOL", "name": "_percent_string_end"}
                 ]
               },
             ]
diff --git a/src/compiler/build_tables/build_parse_table.cc b/src/compiler/build_tables/build_parse_table.cc
index 4c3ba8c6..bdaac037 100644
--- a/src/compiler/build_tables/build_parse_table.cc
+++ b/src/compiler/build_tables/build_parse_table.cc
@@ -584,7 +584,7 @@ class ParseTableBuilder {
         return grammar.variables[symbol.index].name;
       }
       case Symbol::External: {
-        return grammar.external_tokens[symbol.index];
+        return grammar.external_tokens[symbol.index].name;
       }
     }
   }
diff --git a/src/compiler/generate_code/c_code.cc b/src/compiler/generate_code/c_code.cc
index db8756e6..e5272595 100644
--- a/src/compiler/generate_code/c_code.cc
+++ b/src/compiler/generate_code/c_code.cc
@@ -485,7 +485,7 @@ class CCodeGenerator {
   // Helper functions
 
   string external_token_id(Symbol::Index index) {
-    return "ts_external_token_" + syntax_grammar.external_tokens[index];
+    return "ts_external_token_" + syntax_grammar.external_tokens[index].name;
   }
 
   string symbol_id(const Symbol &symbol) {
@@ -528,7 +528,8 @@ class CCodeGenerator {
         return { variable.name, variable.type };
       }
       case Symbol::External: {
-        return { syntax_grammar.external_tokens[symbol.index], VariableTypeNamed };
+        const ExternalToken &token = syntax_grammar.external_tokens[symbol.index];
+        return { token.name, token.type };
       }
     }
   }
diff --git a/src/compiler/prepare_grammar/initial_syntax_grammar.h b/src/compiler/prepare_grammar/initial_syntax_grammar.h
index d4b1c8d5..1ac319cb 100644
--- a/src/compiler/prepare_grammar/initial_syntax_grammar.h
+++ b/src/compiler/prepare_grammar/initial_syntax_grammar.h
@@ -15,7 +15,7 @@ struct InitialSyntaxGrammar {
   std::vector<Variable> variables;
   std::set<rules::Symbol> extra_tokens;
   std::set<ConflictSet> expected_conflicts;
-  std::vector<std::string> external_tokens;
+  std::vector<ExternalToken> external_tokens;
 };
 
 }  // namespace prepare_grammar
diff --git a/src/compiler/prepare_grammar/intern_symbols.cc b/src/compiler/prepare_grammar/intern_symbols.cc
index efe4b37f..daad9d2e 100644
--- a/src/compiler/prepare_grammar/intern_symbols.cc
+++ b/src/compiler/prepare_grammar/intern_symbols.cc
@@ -54,7 +54,14 @@ CompileError missing_rule_error(string rule_name) {
 
 pair<InternedGrammar, CompileError> intern_symbols(const Grammar &grammar) {
   InternedGrammar result;
-  result.external_tokens = grammar.external_tokens;
+
+  for (auto &external_token_name : grammar.external_tokens) {
+    result.external_tokens.push_back(ExternalToken{
+      external_token_name,
+      external_token_name[0] == '_' ? VariableTypeHidden : VariableTypeNamed
+    });
+  }
+
   InternSymbols interner(grammar);
 
   for (auto &pair : grammar.rules) {
@@ -62,9 +69,11 @@ pair<InternedGrammar, CompileError> intern_symbols(const Grammar &grammar) {
     if (!interner.missing_rule_name.empty())
       return { result, missing_rule_error(interner.missing_rule_name) };
 
-    result.variables.push_back(Variable(
-      pair.first, pair.first[0] == '_' ? VariableTypeHidden : VariableTypeNamed,
-      new_rule));
+    result.variables.push_back(Variable{
+      pair.first,
+      pair.first[0] == '_' ? VariableTypeHidden : VariableTypeNamed,
+      new_rule
+    });
   }
 
   for (auto &rule : grammar.extra_tokens) {
diff --git a/src/compiler/prepare_grammar/interned_grammar.h b/src/compiler/prepare_grammar/interned_grammar.h
index 7b425c3a..c8a14647 100644
--- a/src/compiler/prepare_grammar/interned_grammar.h
+++ b/src/compiler/prepare_grammar/interned_grammar.h
@@ -15,7 +15,7 @@ struct InternedGrammar {
   std::vector<Variable> variables;
   std::vector<rule_ptr> extra_tokens;
   std::set<ConflictSet> expected_conflicts;
-  std::vector<std::string> external_tokens;
+  std::vector<ExternalToken> external_tokens;
 };
 
 }  // namespace prepare_grammar
diff --git a/src/compiler/syntax_grammar.h b/src/compiler/syntax_grammar.h
index e34ddbbe..3d001b61 100644
--- a/src/compiler/syntax_grammar.h
+++ b/src/compiler/syntax_grammar.h
@@ -10,6 +10,11 @@
 
 namespace tree_sitter {
 
+struct ExternalToken {
+  std::string name;
+  VariableType type;
+};
+
 struct ProductionStep {
   ProductionStep(const rules::Symbol &, int, rules::Associativity);
   bool operator==(const ProductionStep &) const;
@@ -36,7 +41,7 @@ struct SyntaxGrammar {
   std::vector<SyntaxVariable> variables;
   std::set<rules::Symbol> extra_tokens;
   std::set<ConflictSet> expected_conflicts;
-  std::vector<std::string> external_tokens;
+  std::vector<ExternalToken> external_tokens;
 };
 
 }  // namespace tree_sitter