diff --git a/src/extension/extension.cpp b/src/extension/extension.cpp
index 642d39d6ae0cede4016007a81367aeca1dc091e0..c9e8cbe3d40a65da3569bb4267a66a1848f6dad8 100644
--- a/src/extension/extension.cpp
+++ b/src/extension/extension.cpp
@@ -256,15 +256,17 @@ Extension::loaded ()
 bool
 Extension::check ()
 {
-    char const *inx_failure = _("  This is caused by an improper .inx file for this extension."
-                                "  An improper .inx file could have been caused by a faulty installation of Inkscape.");
+    auto get_inx_error_text = []() {
+        return _("  This is caused by an improper .inx file for this extension."
+                 "  An improper .inx file could have been caused by a faulty installation of Inkscape.");
+    };
 
     if (repr == nullptr) {
-        printFailure(Glib::ustring(_("the XML description of it got lost.")) += inx_failure);
+        printFailure(Glib::ustring(_("the XML description of it got lost.")) += get_inx_error_text());
         return false;
     }
     if (!imp) {
-        printFailure(Glib::ustring(_("no implementation was defined for the extension.")) += inx_failure);
+        printFailure(Glib::ustring(_("no implementation was defined for the extension.")) += get_inx_error_text());
         return false;
     }
 
@@ -505,10 +507,26 @@ char const *Extension::get_translation(char const *msgid, char const *msgctxt) c
         return msgid;
     }
 
+    // Possible enhancement: heterogeneous lookup
+    // https://stackoverflow.com/questions/49709548/c-unordered-mapstring-lookup-without-constructing-string
     if (msgctxt) {
-        return g_dpgettext2(_translationdomain, msgctxt, msgid);
+        auto& map = _translations_by_context[msgctxt];
+
+        auto iter = map.find(msgid);
+        if (iter != map.end())
+            return iter->second.c_str(); // TODO: return std::string
+        // Can g_dgettext return NULL?
+        auto emplaced = map.emplace(msgid, g_dpgettext2(_translationdomain, msgctxt, msgid)).first;
+        return emplaced->second.c_str();
     } else {
-        return g_dgettext(_translationdomain, msgid);
+        auto& map = _translations;
+
+        auto iter = map.find(msgid);
+        if (iter != map.end())
+            return iter->second.c_str(); // TODO: return std::string
+        // Can g_dgettext return NULL?
+        auto emplaced = map.emplace(msgid, g_dgettext(_translationdomain, msgid)).first;
+        return emplaced->second.c_str();
     }
 }
 
diff --git a/src/extension/extension.h b/src/extension/extension.h
index 754b779622f230edc728210e0810ff6de2182b1b..f3ed66c6b74bf615e83b5a27690fcf8a4e7225ff 100644
--- a/src/extension/extension.h
+++ b/src/extension/extension.h
@@ -23,6 +23,7 @@
 #include <memory>
 #include <string>
 #include <vector>
+#include <unordered_map>
 
 #include <glibmm/ustring.h>
 #include <sigc++/signal.h>
@@ -152,6 +153,11 @@ private:
 
     std::vector<ProcessingAction> _actions;    /**< Processing actions */
 
+    using string_map = std::unordered_map<std::string, std::string>;
+    // TODO: use separate object instead of mutable? Or remove const from some methods?
+    mutable std::unordered_map<std::string, string_map> _translations_by_context; /**< Caches of intl translations by context */
+    mutable std::unordered_map<std::string, std::string> _translations; /**< Cache of intl translations */
+
 protected:
     Inkscape::XML::Node *repr;                 /**< The XML description of the Extension */