diff --git a/README.md b/README.md
index 1ac8714..eb9868e 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,8 @@ but on Telegram.
 Bot uses an OOP-style of lua
 as [described on Wikipedia](https://is.gd/f0Vadk)
 
+Also, bot automatically detects language installed in the client.
+
 TODO: Rewrite core to C, [lua have C API](https://www.lua.org/manual/5.3/manual.html#4)
 and C is faster.
 
diff --git a/config.lua b/config.lua
index ca07dba..7d51506 100644
--- a/config.lua
+++ b/config.lua
@@ -3,12 +3,17 @@ return {
   owner = 935626920 , -- hehe
   cmds = {
     'eval',
-    'rub',
     'ping',
+    'rub',
+    'start',
   },
   events = {
     'command',
-    'message',
     'ready',
   },
-}
\ No newline at end of file
+  parts = {
+    'locale',
+    'db',
+    'client',
+  },
+}
diff --git a/etc/api/core.lua b/etc/api/core.lua
index 2db4bba..73c73f4 100644
--- a/etc/api/core.lua
+++ b/etc/api/core.lua
@@ -30,20 +30,24 @@ local function receiveUpdate(self, update)
   if update then self:emit('update', update) end
 
   if update.message then
-    local txt = update.message.text
-    local cmd, to = tools.fetchCmd(txt)
+    local msg = update.message
+    local cmd, to = tools.fetchCmd(msg.text or '')
     if cmd and (not to or to == self.info.username) then
+      -- need /cmd@bot in groups
+      if (msg.chat.type == 'group' or msg.chat.type == 'supergroup')
+       and not to then return end
+
       local args = {}
-      txt = txt:sub(#cmd + #(to or {}) + 3)
-      for s in txt:gmatch '%S+' do table.insert(args, s) end
+      txt = msg.text:sub(#cmd + #(to or {}) + 3)
+      for s in msg.text:gmatch '%S+' do table.insert(args, s) end
 
-      update.message.cmd = cmd
-      update.message.args = args
+      msg.cmd  = cmd
+      msg.args = args
 
-      return self:emit('command', update.message)
+      return self:emit('command', msg)
     elseif cmd then return end
 
-    self:emit('message', update.message)
+    self:emit('message', msg)
 
   elseif update.edited_message then
     self:emit('messageEdit', update.edited_message)
diff --git a/src/cmds/eval.lua b/src/cmds/eval.lua
index ec342d4..e430daf 100644
--- a/src/cmds/eval.lua
+++ b/src/cmds/eval.lua
@@ -29,8 +29,6 @@ local env = {
 
 return {
   private = true,
-  args = '<code>',
-  desc = 'evaluates code',
   run = function(C, msg, owner)
     local s = ''
     local t = {
diff --git a/src/cmds/ping.lua b/src/cmds/ping.lua
index cea65dd..926cef7 100644
--- a/src/cmds/ping.lua
+++ b/src/cmds/ping.lua
@@ -1,6 +1,5 @@
 return {
-  desc = 'ping pong',
   run = function(C, msg)
-    C.api:send(msg, 'Pong! ' .. (os.time() - msg.date) .. 's')
+    C.api:send(msg, msg.loc.pat:format(os.time() - msg.date))
   end
 }
\ No newline at end of file
diff --git a/src/cmds/rub.lua b/src/cmds/rub.lua
index 113c74e..8c7b1c1 100644
--- a/src/cmds/rub.lua
+++ b/src/cmds/rub.lua
@@ -5,64 +5,56 @@
 local rub = {
   url = 'https://api.factmaven.com/xml-to-json/?xml='
     .. 'https://www.cbr.ru/scripts/XML_daily.asp',
-  fmt = function(v, fmt)
-    fmt = type(fmt) == 'string' and fmt or '%d %s = %f'
-    return fmt:format(v.Nominal, v.Name, v.Value:gsub(',', '.'))
-  end
+
+  tools = require 'etc.api.tools',
 }
 
-function rub:course(wants, fmt)
-  local resp, succ = (require 'etc.api.tools').requ(self.url)
-  if not succ then
-    return {}, '[ошибка]', {}
-  end
+function rub:course(wants)
+  local resp, succ = self.tools.requ(self.url)
+  if not succ then return 'err' end
 
   resp = resp.ValCurs
+  table.insert(resp.Valute, {
+    ID = 'R01000',
+    NumCode = '001',
+    CharCode = 'RUB',
+    Nominal = 1,
+    Name = 'Российский рубль',
+    Value = '1'
+  })
 
   wants = type(wants) == 'table' and wants or {}
   local r, founds = {}, {}
+
   for i = 1, #resp.Valute do
     local v = resp.Valute[i]
     if table.find(wants, v.CharCode) then
       table.insert(founds, v.CharCode)
-      table.insert(r, self.fmt(v, fmt))
+      table.insert(r, ('%d %s (%s) - %f ₽'):format(v.Nominal, v.Name, v.CharCode, v.Value:gsub(',', '.')))
     end
   end
 
-  local i = table.find(wants, 'RUB')
-  if i then
-    table.insert(founds, 'RUB')
-    table.insert(r, i, self.fmt({
-      Nominal = 1,
-      Name = 'Российский рубль',
-      Value = '1'
-    }, fmt) .. ' :D')
-  end
-
   return r, resp.Date, founds
 end
 
-function rub.msg(C, msg)
-  local wants = {'USD', 'EUR', table.unpack(msg.args)}
-  for i = 1, #wants do wants[i] = wants[i]:upper() end
-
-  local v, d, f = rub:course(wants, '%d %s - %f ₽')
-  local nf = {}
-
-  for i = 1, #wants do
-    if not table.find(f, wants[i]) then
-      table.insert(nf, wants[i])
-    end
-  end
-
-  local s = 'Курс на ' .. d .. ':\n' .. table.concat(v, '\n')
-  if #nf > 0 then s = s .. '\n\n' .. 'Не нашлось: ' .. table.concat(nf, ', ') end
-
-  C.api:reply(msg, s .. '\nДанные от Центробанка России')
-end
-
 return {
-  args = '[valute]...',
-  desc = 'ruble course',
-  run = rub.msg
+  run = function(C, msg)
+    local wants = {'USD', 'EUR', table.unpack(msg.args)}
+    for i = 1, #wants do wants[i] = wants[i]:upper() end -- uppercase
+
+    local v, d, f = rub:course(wants)
+    if v == 'error' then
+      return C.api:reply(msg, C.locale:get('error', 'req_err'))
+    end
+
+    local nf = {}
+    for _, i in pairs(wants) do
+      if not table.find(f, i) then table.insert(nf, i) end
+    end
+
+    local s = msg.loc.cur:format(d, table.concat(v, '\n'))
+    if #nf > 0 then s = s .. msg.loc.notf .. table.concat(nf, ',') end
+
+    C.api:reply(msg, s .. msg.loc.prov)
+  end
 }
diff --git a/src/cmds/start.lua b/src/cmds/start.lua
new file mode 100644
index 0000000..efc2688
--- /dev/null
+++ b/src/cmds/start.lua
@@ -0,0 +1,6 @@
+return {
+  hide = true,
+  run = function(C, msg)
+    C.api:reply(msg, 'TODO!')
+  end
+}
\ No newline at end of file
diff --git a/src/events/command.lua b/src/events/command.lua
index 9bf9d0a..73e26a4 100644
--- a/src/events/command.lua
+++ b/src/events/command.lua
@@ -1,23 +1,25 @@
 return function(C, api, msg)
   local cmd = C.cmds[msg.cmd]
   local owner = msg.from.id == C.config.owner
+
   if cmd == nil then
-    api:send(msg, 'Invaid command provided.')
+    api:send(msg, C.locale:get('error', 'inv_cmd'))
 
   elseif type(cmd.run) ~= 'function' then
-    api:send(msg, 'Command cannot be executed.')
+    api:send(msg, C.locale:get('error', 'cmd_run'))
 
   elseif cmd.private and not owner then
-    api:send(msg, 'You can\'t execute private commands!')
+    api:send(msg, C.locale:get('error', 'adm_cmd'))
 
   else
+    msg.loc = C.locale:get('cmds', msg.cmd)
     local succ, err = pcall(cmd.run, C, msg, owner)
     if not succ then
-      api:reply(msg, 'Произошла ошибочка, которая была отправлена создателю')
       print(err)
       local cid = C.config.owner
       api:forward(cid, msg.chat.id, msg.message_id, false)
       api:send(cid, err)
+      api:reply(msg, msg.locale.error.not_suc)
     end
   end
 end
\ No newline at end of file
diff --git a/src/events/message.lua b/src/events/message.lua
deleted file mode 100644
index a864740..0000000
--- a/src/events/message.lua
+++ /dev/null
@@ -1,3 +0,0 @@
-return function(C, api, msg)
---  api:reply(msg, 'хай!')
-end
diff --git a/src/events/ready.lua b/src/events/ready.lua
index 1af8c5a..8790990 100644
--- a/src/events/ready.lua
+++ b/src/events/ready.lua
@@ -29,10 +29,11 @@ return function(C, api)
   C:load 'cmds'
   local a = {}
   for k, v in pairs(C.cmds) do
-    if not v.private then
+    if not (v.private or v.hide) then
+      local cmd = C.locale:get('cmds', k) or {}
       table.insert(a, {
         command = k,
-        description = (v.args and v.args .. ' - ' or '') .. v.desc or 'no description'
+        description = (cmd.args and cmd.args .. ' - ' or '') .. (cmd.desc or C.locale:get('cmds', 'not_des'))
       })
     end
   end
diff --git a/src/locales/en.json b/src/locales/en.json
new file mode 100644
index 0000000..55a04fc
--- /dev/null
+++ b/src/locales/en.json
@@ -0,0 +1,31 @@
+{
+  "error": {
+    "inv_cmd": "Invalid command provided.",
+    "adm_cmd": "You can't execute admin commands!",
+    "cmd_run": "This command cannot be executed now.",
+    "not_suc": "An error was occured which already sent to creator.",
+    "unk_err": "Unknown error.",
+    "req_err": "Request error."
+  },
+  "cmds": {
+    "not_des": "no description",
+
+    "eval": {
+      "args": "<code>",
+      "desc": "executes code"
+    },
+    "ping": {
+      "desc": "ping pong",
+
+      "pat": "Pong! %ds"
+    },
+    "rub": {
+      "args": "[valute]...",
+      "desc": "ruble course",
+
+      "cur": "Currency at %s:\n%s",
+      "notf": "\nNot found: ",
+      "prov": "\nData provided from central bank of Russia."
+    }
+  }
+}
diff --git a/src/locales/ru.json b/src/locales/ru.json
new file mode 100644
index 0000000..82fe87c
--- /dev/null
+++ b/src/locales/ru.json
@@ -0,0 +1,31 @@
+{
+  "error": {
+    "inv_cmd": "Указана неизвестная команда.",
+    "adm_cmd": "Вы не можете исполнять админские команды!",
+    "cmd_run": "Это команда не мжет быть выполнена сейчас.",
+    "not_suc": "Произошла ошибка, которая уже отправлена создателю.",
+    "unk_err": "Неизвестная ошибка.",
+    "req_err": "Ошибка запроса."
+  },
+  "cmds": {
+    "not_des": "нет описания",
+
+    "eval": {
+      "args": "<код>",
+      "desc": "исполняет код"
+    },
+    "ping": {
+      "desc": "пинг-понг",
+
+      "pat": "Понг! %d секунд"
+    },
+    "rub": {
+      "args": "[валюта]...",
+      "desc": "курс рубля",
+
+      "cur": "Курс на %s:\n%s",
+      "notf": "\nНе нашлось: ",
+      "prov": "\nДанные предоставлены центральным банком России."
+    }
+  }
+}
diff --git a/src/parts/core.lua b/src/parts/core.lua
index 58938ba..b152c57 100644
--- a/src/parts/core.lua
+++ b/src/parts/core.lua
@@ -28,8 +28,11 @@ end
 function Core:ev(t, i, name, ...)
   local v = t[i]
   if v.name == name then
-    local succ = pcall(v.fn, self, ...)
-    if not succ then print('event "' .. name .. '" was failed') end
+    local succ, err = pcall(v.fn, self, ...)
+    if not succ then
+      print('event "' .. name .. '" was failed')
+      print(err)
+    end
     if v.type == 'once' then table.remove(t, i) end
   end
 end
diff --git a/src/parts/locale.lua b/src/parts/locale.lua
new file mode 100644
index 0000000..f5b2bc1
--- /dev/null
+++ b/src/parts/locale.lua
@@ -0,0 +1,33 @@
+local Locale = {
+  list = {
+    'en',
+    'ru'
+  },
+  main = 'en',
+
+  __newindex = function()end -- ro
+}
+Locale.__index = Locale
+
+function Locale:get(cat, k, lang)
+  assert(cat, 'Give category')
+  assert(k,   'Give key')
+  lang = lang or self.main
+
+  local v = self[lang][cat][k]
+  if not v then
+    return self[self.main][cat][k]
+  else return v end
+end
+
+return function(C)
+  local json = require 'etc.json'
+
+  for i = 1, #Locale.list do
+    local n = Locale.list[i]
+    local f = io.open(('src/locales/%s.json'):format(n))
+    Locale[n] = json.decode(f:read 'a')
+  end
+
+  C.locale = setmetatable({}, Locale)
+end