diff --git a/TestApp/Program.cs b/TestApp/Program.cs
index 4f0c0ed..98085ac 100644
--- a/TestApp/Program.cs
+++ b/TestApp/Program.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 using ZeroLevel;
 
 namespace TestApp
@@ -18,4 +19,4 @@ namespace TestApp
             Bootstrap.Shutdown();
         }
     }
-}
+}
\ No newline at end of file
diff --git a/ZeroLevel.UnitTests/SemanticTests.cs b/ZeroLevel.UnitTests/SemanticTests.cs
new file mode 100644
index 0000000..ba16b1d
--- /dev/null
+++ b/ZeroLevel.UnitTests/SemanticTests.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Xunit;
+using ZeroLevel.Services.Semantic;
+
+namespace ZeroLevel.UnitTests
+{
+    public class SemanticTests
+    {
+        [Fact]
+        public void WordTokenizerTest()
+        {
+            // Arrange            
+            var line = "Хорошее понимание проекций, отражений и векторных операций (как в истинном значении скалярного (dot) и векторного (cross) произведений векторов) обычно приходит с растущим чувством беспокойства при использованием тригонометрии. ";
+            var test = new string[] {
+                "хорошее", "понимание", "проекций", "отражений", "и"
+                , "векторных", "операций", "как", "в", "истинном"
+                , "значении", "скалярного","dot","и","векторного","cross","произведений"
+                ,"векторов","обычно","приходит","с","растущим","чувством","беспокойства"
+                ,"при","использованием", "тригонометрии"};
+            // Act
+            var terms = WordTokenizer.Tokenize(line).ToArray();
+            // Assert
+
+            Assert.True(test.Length == terms.Length);
+            for (int i = 0; i < terms.Length; i++)
+            {
+                Assert.True(string.CompareOrdinal(test[i], terms[i]) == 0);
+            }
+        }
+    }
+}
diff --git a/ZeroLevel/Services/Semantic/LanguageDictionary.cs b/ZeroLevel/Services/Semantic/LanguageDictionary.cs
new file mode 100644
index 0000000..f44f5fd
--- /dev/null
+++ b/ZeroLevel/Services/Semantic/LanguageDictionary.cs
@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using ZeroLevel.Services.Semantic;
+using ZeroLevel.Services.Serialization;
+
+namespace ZeroLevel.Services.Semantic
+{
+    public class LanguageDictionary
+        : IBinarySerializable
+    {
+        private Trie _words = new Trie();
+        public uint this[string word] => _words.Key(word) ?? 0;
+        public string Word(uint key) => _words.Word(key);
+
+        public IEnumerable<uint> Keys => _words.Keys;
+
+        public void Append(string word)
+        {
+            _words.Append(word.Normalize());
+        }
+
+        public void Deserialize(IBinaryReader reader)
+        {
+            this._words = reader.Read<Trie>();
+        }
+
+        public void Serialize(IBinaryWriter writer)
+        {
+            writer.Write(this._words);
+        }
+
+        public void ToggleReverseIndex(bool enabled)
+        {
+            _words.ToggleReverseIndex(enabled);
+        }
+    }
+}
diff --git a/ZeroLevel/Services/Semantic/Trie.cs b/ZeroLevel/Services/Semantic/Trie.cs
index 472c494..31effa7 100644
--- a/ZeroLevel/Services/Semantic/Trie.cs
+++ b/ZeroLevel/Services/Semantic/Trie.cs
@@ -12,7 +12,7 @@ namespace ZeroLevel.Services.Semantic
         internal class TrieNode
             : IBinarySerializable
         {
-            public char? Key; // settet only with rebuild index
+            public char? Key; // setted only with rebuild index
             public uint? Value;
             public TrieNode Parent;
             public ConcurrentDictionary<char, TrieNode> Children;
diff --git a/ZeroLevel/Services/Semantic/WordTokenizer.cs b/ZeroLevel/Services/Semantic/WordTokenizer.cs
new file mode 100644
index 0000000..17490d2
--- /dev/null
+++ b/ZeroLevel/Services/Semantic/WordTokenizer.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using ZeroLevel.Services.Pools;
+
+namespace ZeroLevel.Services.Semantic
+{
+    public static class WordTokenizer
+    {
+        static ObjectPool<char[]> _pool = new ObjectPool<char[]>(() => new char[2048]);
+
+        public static IEnumerable<string> Tokenize(string text)
+        {
+            int index = 0;
+            bool first = true;
+            var buffer = _pool.Allocate();
+            try
+            {
+                for (int i = 0; i < text.Length; i++)
+                {
+                    if (first && Char.IsLetter(text[i]))
+                    {
+                        first = false;
+                        buffer[index++] = text[i];
+                    }
+                    else if (first == false &&  Char.IsLetterOrDigit(text[i]))
+                    {
+                        buffer[index++] = text[i];
+                    }
+                    else if (index > 0)
+                    {
+                        yield return new string(buffer, 0, index).ToLowerInvariant();
+                        index = 0;
+                        first = true;
+                    }
+                }
+                if (index > 0)
+                {
+                    yield return new string(buffer, 0, index).ToLowerInvariant();
+                }
+            }
+            finally
+            {
+                _pool.Free(buffer);
+            }
+        }
+    }
+}
diff --git a/ZeroLevel/Services/Semantic/WordsDictionary.cs b/ZeroLevel/Services/Semantic/WordsDictionary.cs
new file mode 100644
index 0000000..5c64e25
--- /dev/null
+++ b/ZeroLevel/Services/Semantic/WordsDictionary.cs
@@ -0,0 +1,64 @@
+using System.Collections.Concurrent;
+using System.Threading;
+using ZeroLevel.Services.Serialization;
+
+namespace ZeroLevel.Services.Semantic
+{
+    public class WordsDictionary
+        : IBinarySerializable
+    {
+        private ConcurrentDictionary<string, LanguageDictionary> _dicts = new ConcurrentDictionary<string, LanguageDictionary>();
+        private ReaderWriterLockSlim _lock = new ReaderWriterLockSlim();
+
+        public LanguageDictionary this[string lang]
+        {
+            get
+            {
+                if (_dicts.ContainsKey(lang) == false)
+                {
+                    _lock.EnterWriteLock();
+                    try
+                    {
+                        if (_dicts.ContainsKey(lang) == false)
+                        {
+                            _dicts[lang] = new LanguageDictionary();
+                        }
+                    }
+                    finally
+                    {
+                        _lock.ExitWriteLock();
+                    }
+                }
+                return _dicts[lang];
+            }
+        }
+        public void ToggleReverseIndex(bool enabled)
+        {
+            foreach (var pair in _dicts)
+            {
+                pair.Value.ToggleReverseIndex(enabled);
+            }
+        }
+        public void Deserialize(IBinaryReader reader)
+        {
+            int count = reader.ReadInt32();
+            this._dicts = new ConcurrentDictionary<string, LanguageDictionary>();
+            string key;
+            for (int i = 0; i < count; i++)
+            {
+                key = reader.ReadString();
+                this._dicts.TryAdd(key, reader.Read<LanguageDictionary>());
+            }
+        }
+
+        public void Serialize(IBinaryWriter writer)
+        {
+            writer.WriteInt32(_dicts.Count);
+            foreach (var pair in _dicts)
+            {
+                writer.WriteString(pair.Key);
+                writer.Write<LanguageDictionary>(pair.Value);
+            }
+        }
+    }
+}