diff --git a/securedrop_client/__init__.py b/securedrop_client/__init__.py
index dc7b12a144..fa9c4ec2bc 100644
--- a/securedrop_client/__init__.py
+++ b/securedrop_client/__init__.py
@@ -1,25 +1 @@
-import gettext
-import locale
-import os
-
-
-# Configure locale and language.
-# Define where the translation assets are to be found.
-localedir = os.path.abspath(os.path.join(os.path.dirname(__file__), 'locale'))
-try:
-    # Use the operating system's locale.
-    current_locale, encoding = locale.getdefaultlocale()
-    # Get the language code.
-    if current_locale is None:
-        language_code = 'en'
-    else:
-        language_code = current_locale[:2]
-except ValueError:  # pragma: no cover
-    language_code = 'en'  # pragma: no cover
-# DEBUG/TRANSLATE: override the language code here (e.g. to Chinese).
-# language_code = 'zh'
-gettext.translation('securedrop_client', localedir=localedir,
-                    languages=[language_code], fallback=True).install()
-
-
 __version__ = '0.0.6'
diff --git a/securedrop_client/app.py b/securedrop_client/app.py
index efb06cdc7f..c5c1044be5 100644
--- a/securedrop_client/app.py
+++ b/securedrop_client/app.py
@@ -18,6 +18,8 @@
 """
 import logging
 import os
+import gettext
+import locale
 import platform
 import signal
 import sys
@@ -54,6 +56,27 @@ def excepthook(*exc_args):
     sys.exit(1)
 
 
+def configure_locale_and_language() -> str:
+    # Configure locale and language.
+    # Define where the translation assets are to be found.
+    localedir = os.path.abspath(os.path.join(os.path.dirname(__file__), 'locale'))
+    try:
+        # Use the operating system's locale.
+        current_locale, encoding = locale.getdefaultlocale()
+        # Get the language code.
+        if current_locale is None:
+            language_code = 'en'
+        else:
+            language_code = current_locale[:2]
+    except ValueError:  # pragma: no cover
+        language_code = 'en'  # pragma: no cover
+    # DEBUG/TRANSLATE: override the language code here (e.g. to Chinese).
+    # language_code = 'zh'
+    gettext.translation('securedrop_client', localedir=localedir,
+                        languages=[language_code], fallback=True).install()
+    return language_code
+
+
 def configure_logging(sdc_home: str) -> None:
     """
     All logging related settings are set up by this function.
@@ -140,6 +163,7 @@ def start_app(args, qt_args) -> None:
     Create all the top-level assets for the application, set things up and
     run the application. Specific tasks include:
 
+    - set up locale and language.
     - set up logging.
     - create an application object.
     - create a window for the app.
@@ -148,6 +172,7 @@ def start_app(args, qt_args) -> None:
     - configure the client (logic) object.
     - ensure the application is setup in the default safe starting state.
     """
+    configure_locale_and_language()
     init(args.sdc_home)
     configure_logging(args.sdc_home)
     logging.info('Starting SecureDrop Client {}'.format(__version__))
diff --git a/tests/conftest.py b/tests/conftest.py
index cc3b439aad..da95a4d8b7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -6,6 +6,7 @@
 from configparser import ConfigParser
 from datetime import datetime
 from securedrop_client.config import Config
+from securedrop_client.app import configure_locale_and_language
 from securedrop_client.db import Base, make_engine, Source
 from sqlalchemy.orm import sessionmaker
 from uuid import uuid4
@@ -26,6 +27,7 @@ def homedir():
     '''
 
     tmpdir = tempfile.mkdtemp(prefix='sdc-')
+    configure_locale_and_language()
     os.chmod(tmpdir, 0o0700)
 
     data_dir = os.path.join(tmpdir, 'data')
diff --git a/tests/test_app.py b/tests/test_app.py
index e604ce9c0d..26a3d996f6 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -8,11 +8,17 @@
 from PyQt5.QtWidgets import QApplication
 from securedrop_client.app import ENCODING, excepthook, configure_logging, \
     start_app, arg_parser, DEFAULT_SDC_HOME, run, configure_signal_handlers, \
-    prevent_second_instance
+    prevent_second_instance, configure_locale_and_language
 
 app = QApplication([])
 
 
+def test_application_sets_en_as_default_language_code(mocker):
+    mocker.patch('locale.getdefaultlocale', return_value=(None, None))
+    language_code = configure_locale_and_language()
+    assert language_code == 'en'
+
+
 def test_excepthook(mocker):
     """
     Ensure the custom excepthook logs the error and calls sys.exit.