diff --git a/num2words/__init__.py b/num2words/__init__.py
index b1a266b..07ef2bc 100644
--- a/num2words/__init__.py
+++ b/num2words/__init__.py
@@ -18,11 +18,11 @@
 from __future__ import unicode_literals
 
 from . import (lang_AR, lang_CZ, lang_DE, lang_DK, lang_EN, lang_EN_IN,
-               lang_ES, lang_ES_CO, lang_ES_VE, lang_FI, lang_FR, lang_FR_BE,
-               lang_FR_CH, lang_FR_DZ, lang_HE, lang_ID, lang_IT, lang_JA,
-               lang_KN, lang_KO, lang_LT, lang_LV, lang_NL, lang_NO, lang_PL,
-               lang_PT, lang_PT_BR, lang_RO, lang_RU, lang_SL, lang_SR,
-               lang_TH, lang_TR, lang_UK, lang_VI)
+               lang_ES, lang_ES_CO, lang_ES_NI, lang_ES_VE, lang_FI, lang_FR,
+               lang_FR_BE, lang_FR_CH, lang_FR_DZ, lang_HE, lang_ID, lang_IT,
+               lang_JA, lang_KN, lang_KO, lang_LT, lang_LV, lang_NL, lang_NO,
+               lang_PL, lang_PT, lang_PT_BR, lang_RO, lang_RU, lang_SL,
+               lang_SR, lang_TH, lang_TR, lang_UK, lang_VI)
 
 CONVERTER_CLASSES = {
     'ar': lang_AR.Num2Word_AR(),
@@ -37,6 +37,7 @@ CONVERTER_CLASSES = {
     'fi': lang_FI.Num2Word_FI(),
     'es': lang_ES.Num2Word_ES(),
     'es_CO': lang_ES_CO.Num2Word_ES_CO(),
+    'es_NI': lang_ES_NI.Num2Word_ES_NI(),
     'es_VE': lang_ES_VE.Num2Word_ES_VE(),
     'id': lang_ID.Num2Word_ID(),
     'ja': lang_JA.Num2Word_JA(),
diff --git a/num2words/lang_ES_NI.py b/num2words/lang_ES_NI.py
new file mode 100644
index 0000000..9e5f9e8
--- /dev/null
+++ b/num2words/lang_ES_NI.py
@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2003, Taro Ogawa.  All Rights Reserved.
+# Copyright (c) 2013, Savoir-faire Linux inc.  All Rights Reserved.
+
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+# MA 02110-1301 USA
+
+from __future__ import print_function, unicode_literals
+
+from .lang_ES import Num2Word_ES
+
+
+class Num2Word_ES_NI(Num2Word_ES):
+    CURRENCY_FORMS = {
+        'NIO': (('córdoba', 'córdobas'), ('centavo', 'centavos')),
+    }
+
+    def to_currency(self, val, currency='NIO', cents=True, separator=' con',
+                    adjective=False):
+        result = super(Num2Word_ES, self).to_currency(
+            val, currency=currency, cents=cents, separator=separator,
+            adjective=adjective)
+        return result.replace("uno", "un")
diff --git a/num2words/lang_RU.py b/num2words/lang_RU.py
index 3b02526..e822d38 100644
--- a/num2words/lang_RU.py
+++ b/num2words/lang_RU.py
@@ -107,6 +107,12 @@ class Num2Word_RU(Num2Word_Base):
         'USD': (
             ('доллар', 'доллара', 'долларов'), ('цент', 'цента', 'центов')
         ),
+        'UAH': (
+            ('гривна', 'гривны', 'гривен'), ('копейка', 'копейки', 'копеек')
+        ),
+        'KZT': (
+            ('тенге', 'тенге', 'тенге'), ('тиын', 'тиына', 'тиынов')
+        ),
     }
 
     def setup(self):
diff --git a/tests/test_errors.py b/tests/test_errors.py
new file mode 100644
index 0000000..fedc16e
--- /dev/null
+++ b/tests/test_errors.py
@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2003, Taro Ogawa.  All Rights Reserved.
+# Copyright (c) 2013, Savoir-faire Linux inc.  All Rights Reserved.
+
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+# MA 02110-1301 USA
+
+from __future__ import unicode_literals
+
+from unittest import TestCase
+
+from num2words import num2words
+
+
+class Num2WordsErrorsTest(TestCase):
+
+    def test_NotImplementedError(self):
+        with self.assertRaises(NotImplementedError):
+            num2words(100, lang="lalala")
diff --git a/tests/test_es_ni.py b/tests/test_es_ni.py
new file mode 100644
index 0000000..619e6a1
--- /dev/null
+++ b/tests/test_es_ni.py
@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2003, Taro Ogawa.  All Rights Reserved.
+# Copyright (c) 2013, Savoir-faire Linux inc.  All Rights Reserved.
+
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+# MA 02110-1301 USA
+
+from __future__ import unicode_literals
+
+from num2words import num2words
+
+from . import test_es
+
+TEST_NIO = (
+    (1.0, 'un córdoba con cero centavos'),
+    (2.0, 'dos córdobas con cero centavos'),
+    (8.0, 'ocho córdobas con cero centavos'),
+    (12.0, 'doce córdobas con cero centavos'),
+    (21.0, 'veintiun córdobas con cero centavos'),
+    (81.25, 'ochenta y un córdobas con veinticinco centavos'),
+    (100.00, 'cien córdobas con cero centavos'),
+)
+
+
+class Num2WordsESNITest(test_es.Num2WordsESTest):
+
+    def test_currency(self):
+        for test in TEST_NIO:
+            self.assertEqual(
+                num2words(test[0], lang='es_NI', to='currency'),
+                test[1]
+            )