diff --git a/tests/native/core/test_core.py b/tests/native/core/test_core.py
index 616469e..9e2623a 100644
--- a/tests/native/core/test_core.py
+++ b/tests/native/core/test_core.py
@@ -52,13 +52,14 @@ class TestNative(object):
 
     def _get_tx(self, **kwargs):
         mytx = TxNative()
-        mytx.setup(languages=['en', 'el'], token='cds_token', **kwargs)
+        mytx.setup(source_language='en', languages=['en', 'el'],
+                   token='cds_token', **kwargs)
         return mytx
 
     @patch('transifex.native.core.StringRenderer.render')
     def test_translate_source_language_reaches_renderer(self, mock_render):
         mytx = self._get_tx()
-        mytx.translate('My String', 'en', is_source=True)
+        mytx.translate('My String', 'en')
         mock_render.assert_called_once_with(
             source_string='My String',
             string_to_render='My String',
@@ -74,13 +75,13 @@ def test_translate_target_language_missing_reaches_renderer(self, mock_render,
                                                                 mock_cache):
         mock_cache.return_value = None
         mytx = self._get_tx()
-        mytx.translate('My String', 'en', is_source=False)
+        mytx.translate('My String', 'foo')
         mock_cache.assert_called_once_with(
-            generate_key(string='My String'), 'en')
+            generate_key(string='My String'), 'foo')
         mock_render.assert_called_once_with(
             source_string='My String',
             string_to_render=None,
-            language_code='en',
+            language_code='foo',
             escape=True,
             missing_policy=mytx._missing_policy,
             params={},
@@ -89,7 +90,7 @@ def test_translate_target_language_missing_reaches_renderer(self, mock_render,
     def test_translate_target_language_missing_reaches_missing_policy(self):
         missing_policy = MagicMock()
         mytx = self._get_tx(missing_policy=missing_policy)
-        mytx.translate('My String', 'en', is_source=False)
+        mytx.translate('My String', 'foo')
         missing_policy.get.assert_called_once_with('My String')
 
     @patch('transifex.native.core.StringRenderer')
@@ -97,10 +98,10 @@ def test_translate_error_reaches_error_policy(self, mock_renderer):
         error_policy = MagicMock()
         mock_renderer.render.side_effect = Exception
         mytx = self._get_tx(error_policy=error_policy)
-        mytx.translate('My String', 'en', is_source=False)
+        mytx.translate('My String', 'en')
         error_policy.get.assert_called_once_with(
-            source_string='My String', translation=None, language_code='en',
-            escape=True, params={},
+            source_string='My String', translation="My String",
+            language_code='en', escape=True, params={},
         )
 
     def test_translate_error_reaches_source_string_error_policy(
@@ -111,7 +112,7 @@ def test_translate_error_reaches_source_string_error_policy(
         mock_missing_policy = MagicMock()
         mock_missing_policy.get.side_effect = Exception
         mytx = self._get_tx(missing_policy=mock_missing_policy)
-        result = mytx.translate('My String', 'en', is_source=False)
+        result = mytx.translate('My String', 'en')
         assert result == 'My String'
 
     @patch('transifex.native.core.StringRenderer')
@@ -130,7 +131,7 @@ def test_source_string_policy_custom_text(
         mytx = self._get_tx(
             error_policy=error_policy
         )
-        result = mytx.translate('My String', 'en', is_source=False)
+        result = mytx.translate('My String', 'en')
         assert result == 'my-default-text'
 
     def test_translate_source_language_renders_icu(self):
@@ -138,7 +139,6 @@ def test_translate_source_language_renders_icu(self):
         translation = mytx.translate(
             u'{cnt, plural, one {{cnt} duck} other {{cnt} ducks}}',
             'en',
-            is_source=True,
             params={'cnt': 1}
         )
         assert translation == '1 duck'
@@ -149,8 +149,7 @@ def test_translate_target_language_renders_icu(self, mock_cache):
         mytx = self._get_tx()
         translation = mytx.translate(
             u'{cnt, plural, one {{cnt} duck} other {{cnt} ducks}}',
-            'en',
-            is_source=False,
+            'el',
             params={'cnt': 1}
         )
         assert translation == u'1 παπί'
@@ -160,7 +159,6 @@ def test_translate_source_language_escape_html_true(self):
         translation = mytx.translate(
             u'<script type="text/javascript">alert(1)</script>',
             'en',
-            is_source=True,
             escape=True,
             params={'cnt': 1}
         )
@@ -173,7 +171,6 @@ def test_translate_source_language_escape_html_false(self):
         translation = mytx.translate(
             u'<script type="text/javascript">alert(1)</script>',
             'en',
-            is_source=True,
             escape=False,
             params={'cnt': 1}
         )
diff --git a/tests/native/django/test_templatetag.py b/tests/native/django/test_templatetag.py
index 1bb6ee9..a678ad5 100644
--- a/tests/native/django/test_templatetag.py
+++ b/tests/native/django/test_templatetag.py
@@ -6,6 +6,8 @@
 from transifex.native import tx
 from transifex.native.rendering import SourceStringPolicy
 
+tx.setup(source_language="en_US")
+
 
 def do_test(template_str, context_dict=None, autoescape=True,
             lang_code="en-us"):
diff --git a/transifex/native/core.py b/transifex/native/core.py
index 3e74837..9cec86f 100644
--- a/transifex/native/core.py
+++ b/transifex/native/core.py
@@ -101,7 +101,7 @@ def fetch_translations(self, language_code=None, force=False):
                 self._cache.update(translations)
 
     def translate(
-        self, source_string, language_code=None, is_source=False,
+        self, source_string, language_code=None, 
         _context=None, escape=True, params=None
     ):
         """Translate the given string to the provided language.
@@ -109,8 +109,6 @@ def translate(
         :param unicode source_string: the source string to get the translation
             for e.g. 'Order: {num, plural, one {A table} other {{num} tables}}'
         :param str language_code: the language to translate to
-        :param bool is_source: a boolean indicating whether `translate`
-            is being used for the source language
         :param unicode _context: an optional context that accompanies
             the string
         :param bool escape: if True, the returned string will be HTML-escaped,
@@ -129,8 +127,7 @@ def translate(
 
         translation_template = self.get_translation(source_string,
                                                     language_code,
-                                                    _context,
-                                                    is_source)
+                                                    _context)
 
         return self.render_translation(translation_template,
                                        params,
@@ -138,8 +135,7 @@ def translate(
                                        language_code,
                                        escape)
 
-    def get_translation(self, source_string, language_code, _context,
-                        is_source=False):
+    def get_translation(self, source_string, language_code, _context):
         """ Try to retrieve the translation.
 
             A translation is a serialized source_string with ICU format
@@ -147,7 +143,7 @@ def get_translation(self, source_string, language_code, _context,
             '{num, plural, one {Ένα τραπέζι} other {{num} τραπέζια}}'
         """
 
-        if is_source:
+        if language_code == self.source_language_code:
             translation_template = source_string
         else:
             pluralized, plurals = parse_plurals(source_string)
diff --git a/transifex/native/django/templatetags/transifex.py b/transifex/native/django/templatetags/transifex.py
index fb87e75..5e31147 100644
--- a/transifex/native/django/templatetags/transifex.py
+++ b/transifex/native/django/templatetags/transifex.py
@@ -2,7 +2,6 @@
 
 from copy import copy
 
-from django.conf import settings
 from django.template import Library, Node, TemplateSyntaxError
 from django.template.base import (BLOCK_TAG_END, BLOCK_TAG_START,
                                   COMMENT_TAG_END, COMMENT_TAG_START,
@@ -207,11 +206,9 @@ def render(self, context):
         # ICU template. Then we perform ICU rendering against 'params'.
         # Inbetween the two steps, if the tag used was 't' and not 'ut', we
         # peform escaping on the ICU template.
-        is_source = get_language() == settings.LANGUAGE_CODE
         locale = to_locale(get_language())  # e.g. from en-us to en_US
         translation_icu_template = tx.get_translation(
             source_icu_template, locale, params.get('_context', None),
-            is_source,
         )
         if self.tag_name == "t":
             source_icu_template = escape_html(source_icu_template)
diff --git a/transifex/native/django/utils/__init__.py b/transifex/native/django/utils/__init__.py
index 76f06bd..8f1593a 100644
--- a/transifex/native/django/utils/__init__.py
+++ b/transifex/native/django/utils/__init__.py
@@ -1,4 +1,3 @@
-from django.conf import settings
 from django.utils.translation import get_language, to_locale
 from transifex.common.strings import LazyString
 from transifex.native import tx
@@ -19,13 +18,11 @@ def translate(_string, _context=None, _escape=True, **params):
     :return: the final translation in the current language
     :rtype: unicode
     """
-    is_source = get_language() == settings.LANGUAGE_CODE
     locale = to_locale(get_language())  # e.g. from en-us to en_US
     return tx.translate(
         _string,
         locale,
         _context=_context,
-        is_source=is_source,
         escape=_escape,
         params=params,
     )