diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
index a629bde1..57001ce5 100644
--- a/pre_commit/languages/node.py
+++ b/pre_commit/languages/node.py
@@ -24,7 +24,7 @@ def in_env(repo_cmd_runner):
     yield NodeEnv(repo_cmd_runner)
 
 
-def install_environment(repo_cmd_runner):
+def install_environment(repo_cmd_runner, version='default'):
     assert repo_cmd_runner.exists('package.json')
 
     with clean_path_on_failure(repo_cmd_runner.path(python.ENVIRONMENT_DIR)):
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
index c7fb518f..68a38887 100644
--- a/pre_commit/languages/python.py
+++ b/pre_commit/languages/python.py
@@ -18,7 +18,7 @@ def in_env(repo_cmd_runner):
     yield PythonEnv(repo_cmd_runner)
 
 
-def install_environment(repo_cmd_runner):
+def install_environment(repo_cmd_runner, version='default'):
     assert repo_cmd_runner.exists('setup.py')
 
     # Install a virtualenv
diff --git a/pre_commit/languages/ruby.py b/pre_commit/languages/ruby.py
index 14dd47b6..87b740c6 100644
--- a/pre_commit/languages/ruby.py
+++ b/pre_commit/languages/ruby.py
@@ -56,7 +56,7 @@ def _install_rbenv(repo_cmd_runner):
         )
 
 
-def install_environment(repo_cmd_runner):
+def install_environment(repo_cmd_runner, version='default'):
     with clean_path_on_failure(repo_cmd_runner.path('rbenv')):
         _install_rbenv(repo_cmd_runner)
         with in_env(repo_cmd_runner) as ruby_env:
diff --git a/pre_commit/languages/script.py b/pre_commit/languages/script.py
index 9031410e..411e48ad 100644
--- a/pre_commit/languages/script.py
+++ b/pre_commit/languages/script.py
@@ -1,7 +1,7 @@
 ENVIRONMENT_DIR = None
 
 
-def install_environment(repo_cmd_runner):
+def install_environment(repo_cmd_runner, version='default'):
     """Installation for script type is a noop."""
 
 
diff --git a/pre_commit/languages/system.py b/pre_commit/languages/system.py
index eeea2c50..486b965c 100644
--- a/pre_commit/languages/system.py
+++ b/pre_commit/languages/system.py
@@ -4,7 +4,7 @@ import shlex
 ENVIRONMENT_DIR = None
 
 
-def install_environment(repo_cmd_runner):
+def install_environment(repo_cmd_runner, version='default'):
     """Installation for system type is a noop."""
 
 
diff --git a/pre_commit/repository.py b/pre_commit/repository.py
index 2fe7a00e..7f762d31 100644
--- a/pre_commit/repository.py
+++ b/pre_commit/repository.py
@@ -29,7 +29,10 @@ class Repository(object):
 
     @cached_property
     def languages(self):
-        return set(hook['language'] for hook in self.hooks.values())
+        return set(
+            (hook['language'], hook['language_version'])
+            for hook in self.hooks.values()
+        )
 
     @cached_property
     def hooks(self):
@@ -56,7 +59,7 @@ class Repository(object):
 
     def install(self):
         """Install the hook repository."""
-        for language_name in self.languages:
+        for language_name, language_version in self.languages:
             language = languages[language_name]
             if (
                 language.ENVIRONMENT_DIR is None or
@@ -64,7 +67,7 @@ class Repository(object):
             ):
                 # The language is already installed
                 continue
-            language.install_environment(self.cmd_runner)
+            language.install_environment(self.cmd_runner, language_version)
 
     def run_hook(self, hook_id, file_args):
         """Run a hook.
diff --git a/tests/repository_test.py b/tests/repository_test.py
index b5330801..8beaeff5 100644
--- a/tests/repository_test.py
+++ b/tests/repository_test.py
@@ -113,7 +113,7 @@ def test_sha(mock_repo_config):
 @pytest.mark.integration
 def test_languages(config_for_python_hooks_repo, store):
     repo = Repository.create(config_for_python_hooks_repo, store)
-    assert repo.languages == set(['python'])
+    assert repo.languages == set([('python', 'default')])
 
 
 def test_reinstall(config_for_python_hooks_repo, store):