diff --git a/src/rime/dict/user_dictionary.cc b/src/rime/dict/user_dictionary.cc
index 078d3d984..2c7b9869a 100644
--- a/src/rime/dict/user_dictionary.cc
+++ b/src/rime/dict/user_dictionary.cc
@@ -9,6 +9,7 @@
 #include <boost/lexical_cast.hpp>
 #include <boost/scope_exit.hpp>
 #include <rime/common.h>
+#include <rime/language.h>
 #include <rime/schema.h>
 #include <rime/service.h>
 #include <rime/ticket.h>
@@ -116,8 +117,8 @@ bool UserDictEntryIterator::Next() {
 
 // UserDictionary members
 
-UserDictionary::UserDictionary(const an<Db>& db)
-    : db_(db) {
+UserDictionary::UserDictionary(const string& name, an<Db> db)
+    : name_(name), db_(db) {
 }
 
 UserDictionary::~UserDictionary() {
@@ -494,10 +495,8 @@ UserDictionary* UserDictionaryComponent::Create(const Ticket& ticket) {
     // user specified name
   }
   else if (config->GetString(ticket.name_space + "/dictionary", &dict_name)) {
-    // {dictionary: lunapinyin.extra} implies {user_dict: luna_pinyin}
-    size_t dot = dict_name.find('.');
-    if (dot != string::npos && dot != 0)
-      dict_name.resize(dot);
+    // {dictionary: luna_pinyin.extra} implies {user_dict: luna_pinyin}
+    dict_name = Language::get_language_component(dict_name);
   }
   else {
     LOG(ERROR) << ticket.name_space << "/dictionary not specified in schema '"
@@ -519,7 +518,7 @@ UserDictionary* UserDictionaryComponent::Create(const Ticket& ticket) {
     db.reset(component->Create(dict_name));
     db_pool_[dict_name] = db;
   }
-  return new UserDictionary(db);
+  return new UserDictionary(dict_name, db);
 }
 
 }  // namespace rime
diff --git a/src/rime/dict/user_dictionary.h b/src/rime/dict/user_dictionary.h
index 67f1427fb..4601a22f6 100644
--- a/src/rime/dict/user_dictionary.h
+++ b/src/rime/dict/user_dictionary.h
@@ -50,7 +50,7 @@ struct Ticket;
 
 class UserDictionary : public Class<UserDictionary, const Ticket&> {
  public:
-  explicit UserDictionary(const an<Db>& db);
+  UserDictionary(const string& name, an<Db> db);
   virtual ~UserDictionary();
 
   void Attach(const an<Table>& table, const an<Prism>& prism);
diff --git a/src/rime/gear/memory.cc b/src/rime/gear/memory.cc
index 644bfd7bb..bde9a4785 100644
--- a/src/rime/gear/memory.cc
+++ b/src/rime/gear/memory.cc
@@ -9,6 +9,7 @@
 #include <rime/composition.h>
 #include <rime/engine.h>
 #include <rime/key_event.h>
+#include <rime/language.h>
 #include <rime/schema.h>
 #include <rime/ticket.h>
 #include <rime/dict/dictionary.h>
@@ -65,6 +66,13 @@ Memory::Memory(const Ticket& ticket) {
     }
   }
 
+  // user dictionary is named after language; dictionary name may have an
+  // optional suffix separated from the language component by dot.
+  language_.reset(new Language{
+    user_dict_ ? user_dict_->name() :
+    Language::get_language_component(dict_->name())
+  });
+
   Context* ctx = ticket.engine->context();
   commit_connection_ = ctx->commit_notifier().connect(
       [this](Context* ctx) { OnCommit(ctx); });
@@ -100,7 +108,7 @@ void Memory::OnCommit(Context* ctx) {
   for (auto& seg : ctx->composition()) {
     auto phrase = As<Phrase>(Candidate::GetGenuineCandidate(
             seg.GetSelectedCandidate()));
-    bool recognized = phrase && phrase->language() == language();
+    bool recognized = Language::intelligible(phrase, this);
     if (recognized) {
       commit_entry.AppendPhrase(phrase);
     }
@@ -119,8 +127,7 @@ void Memory::OnDeleteEntry(Context* ctx) {
     return;
   auto phrase = As<Phrase>(Candidate::GetGenuineCandidate(
           ctx->GetSelectedCandidate()));
-  bool recognized = phrase && phrase->language() == language();
-  if (recognized) {
+  if (Language::intelligible(phrase, this)) {
     const DictEntry& entry(phrase->entry());
     LOG(INFO) << "deleting entry: '" << entry.text << "'.";
     user_dict_->UpdateEntry(entry, -1);  // mark as deleted in user dict
diff --git a/src/rime/gear/memory.h b/src/rime/gear/memory.h
index 5ec8145f7..0b065491f 100644
--- a/src/rime/gear/memory.h
+++ b/src/rime/gear/memory.h
@@ -17,6 +17,7 @@ class Context;
 class Engine;
 class Dictionary;
 class UserDictionary;
+class Language;
 class Phrase;
 class Memory;
 
@@ -31,9 +32,6 @@ struct CommitEntry : DictEntry {
   bool Save() const;
 };
 
-class Language {
-};
-
 class Memory {
  public:
   Memory(const Ticket& ticket);
@@ -45,11 +43,11 @@ class Memory {
   bool FinishSession();
   bool DiscardSession();
 
-  Language* language() { return &language_; }
-
   Dictionary* dict() const { return dict_.get(); }
   UserDictionary* user_dict() const { return user_dict_.get(); }
 
+  const Language* language() const { return language_.get(); }
+
  protected:
   void OnCommit(Context* ctx);
   void OnDeleteEntry(Context* ctx);
@@ -57,12 +55,12 @@ class Memory {
 
   the<Dictionary> dict_;
   the<UserDictionary> user_dict_;
+  the<Language> language_;
 
  private:
   connection commit_connection_;
   connection delete_connection_;
   connection unhandled_key_connection_;
-  Language language_;
 };
 
 }  // namespace rime
diff --git a/src/rime/gear/poet.h b/src/rime/gear/poet.h
index 55f0c36b8..df27da549 100644
--- a/src/rime/gear/poet.h
+++ b/src/rime/gear/poet.h
@@ -21,12 +21,12 @@ class Language;
 
 class Poet {
  public:
-  Poet(Language* language) : language_(language) {}
+  Poet(const Language* language) : language_(language) {}
+
+  an<Sentence> MakeSentence(const WordGraph& graph, size_t total_length);
 
-  an<Sentence> MakeSentence(const WordGraph& graph,
-                                    size_t total_length);
  protected:
-  Language* language_;
+  const Language* language_;
 };
 
 }  // namespace rime
diff --git a/src/rime/gear/table_translator.cc b/src/rime/gear/table_translator.cc
index 6f6d0c892..988a21577 100644
--- a/src/rime/gear/table_translator.cc
+++ b/src/rime/gear/table_translator.cc
@@ -28,21 +28,10 @@ static const char* kUnitySymbol = " \xe2\x98\xaf ";
 // TableTranslation
 
 TableTranslation::TableTranslation(TranslatorOptions* options,
-                                   Language* language,
+                                   const Language* language,
                                    const string& input,
-                                   size_t start, size_t end,
-                                   const string& preedit)
-    : options_(options), language_(language),
-      input_(input), start_(start), end_(end), preedit_(preedit) {
-  if (options_)
-    options_->preedit_formatter().Apply(&preedit_);
-  set_exhausted(true);
-}
-
-TableTranslation::TableTranslation(TranslatorOptions* options,
-                                   Language* language,
-                                   const string& input,
-                                   size_t start, size_t end,
+                                   size_t start,
+                                   size_t end,
                                    const string& preedit,
                                    const DictEntryIterator& iter,
                                    const UserDictEntryIterator& uter)
diff --git a/src/rime/gear/table_translator.h b/src/rime/gear/table_translator.h
index 6b5767310..cd4b01dbe 100644
--- a/src/rime/gear/table_translator.h
+++ b/src/rime/gear/table_translator.h
@@ -50,13 +50,13 @@ class TableTranslator : public Translator,
 class TableTranslation : public Translation {
  public:
 
-  TableTranslation(TranslatorOptions* options, Language* language,
-                   const string& input, size_t start, size_t end,
-                   const string& preedit);
-  TableTranslation(TranslatorOptions* options, Language* language,
-                   const string& input, size_t start, size_t end,
+  TableTranslation(TranslatorOptions* options,
+                   const Language* language,
+                   const string& input,
+                   size_t start,
+                   size_t end,
                    const string& preedit,
-                   const DictEntryIterator& iter,
+                   const DictEntryIterator& iter = DictEntryIterator(),
                    const UserDictEntryIterator& uter = UserDictEntryIterator());
 
   virtual bool Next();
@@ -74,7 +74,7 @@ class TableTranslation : public Translation {
   }
 
   TranslatorOptions* options_;
-  Language* language_;
+  const Language* language_;
   string input_;
   size_t start_;
   size_t end_;
diff --git a/src/rime/gear/translator_commons.h b/src/rime/gear/translator_commons.h
index 566a522d2..3367bf41e 100644
--- a/src/rime/gear/translator_commons.h
+++ b/src/rime/gear/translator_commons.h
@@ -70,7 +70,7 @@ class Language;
 
 class Phrase : public Candidate {
  public:
-  Phrase(Language* language,
+  Phrase(const Language* language,
          const string& type, size_t start, size_t end,
          const an<DictEntry>& entry)
       : Candidate(type, start, end),
@@ -93,14 +93,14 @@ class Phrase : public Candidate {
   double weight() const { return entry_->weight; }
   Code& code() const { return entry_->code; }
   const DictEntry& entry() const { return *entry_; }
-  Language* language() const { return language_; }
+  const Language* language() const { return language_; }
   Spans spans() {
     return syllabifier_ ? syllabifier_->Syllabify(this)
                         : Spans();
   }
 
  protected:
-  Language* language_;
+  const Language* language_;
   an<DictEntry> entry_;
   an<PhraseSyllabifier> syllabifier_;
 };
@@ -109,7 +109,7 @@ class Phrase : public Candidate {
 
 class Sentence : public Phrase {
  public:
-  Sentence(Language* language)
+  Sentence(const Language* language)
       : Phrase(language, "sentence", 0, 0, New<DictEntry>()) {
     entry_->weight = 1.0;
   }
diff --git a/src/rime/language.cc b/src/rime/language.cc
new file mode 100644
index 000000000..5626499f8
--- /dev/null
+++ b/src/rime/language.cc
@@ -0,0 +1,18 @@
+//
+// Copyright RIME Developers
+// Distributed under the BSD License
+//
+#include <rime/common.h>
+#include <rime/language.h>
+
+namespace rime {
+
+// "luna_pinyin.extra" has language component "luna_pinyin".
+string Language::get_language_component(const string& name) {
+  size_t dot = name.find('.');
+  if (dot != string::npos && dot != 0)
+    return name.substr(0, dot);
+  return name;
+}
+
+}  // namespace rime
diff --git a/src/rime/language.h b/src/rime/language.h
new file mode 100644
index 000000000..dbc8c0a2b
--- /dev/null
+++ b/src/rime/language.h
@@ -0,0 +1,34 @@
+//
+// Copyright RIME Developers
+// Distributed under the BSD License
+//
+#ifndef RIME_LANGUAGE_H_
+#define RIME_LANGUAGE_H_
+
+#include <rime/common.h>
+
+namespace rime {
+
+class Language {
+  const string name_;
+
+ public:
+  Language(const string& name) : name_(name) {}
+  string name() const { return name_; }
+
+  bool operator== (const Language& other) const {
+    return name_ == other.name_;
+  }
+
+  template <class T, class U>
+  static bool intelligible(const T& t, const U& u) {
+    return t && t->language() && u && u->language() &&
+        *t->language() == *u->language();
+  }
+
+  static string get_language_component(const string& name);
+};
+
+}  // namespace rime
+
+#endif  // RIME_LANGUAGE_H_