diff --git a/dev/containers/fedora-pip-py3 b/dev/containers/fedora-pip-py3
index 5a504ba..61d18e7 100644
--- a/dev/containers/fedora-pip-py3
+++ b/dev/containers/fedora-pip-py3
@@ -18,7 +18,8 @@ RUN dnf -y install \
     gcc \
     redis \
     which \
-    git
+    git \
+    glibc-langpack-en
 
 RUN cd / \
     && git clone -b $BRANCH $REPO \
diff --git a/dev/containers/tox_py3.sh b/dev/containers/tox_py3.sh
index 4c33d1a..859c4e6 100644
--- a/dev/containers/tox_py3.sh
+++ b/dev/containers/tox_py3.sh
@@ -22,4 +22,5 @@ echo "Last commits:"
 git --no-pager log -2
 fi
 
+export LANG="en_US.UTF-8"
 tox -v --sitepackages -e 'py35-flask100-ci' -- --results=results