support other languages.

lib/bcoin/hd.js

@@ -88,6 +88,7 @@ var KeyPair = bcoin.keypair;
 var LRU = require('./lru');
 var BufferWriter = require('./writer');
 var BufferReader = require('./reader');
+var unorm = require('../../vendor/unorm');
 
 /**
  * HD Seed
@@ -148,8 +149,8 @@ Mnemonic.prototype.createSeed = function createSeed() {
     this.phrase = this.createMnemonic();
 
   this.seed = utils.pbkdf2(
-    this.phrase,
-    'mnemonic' + this.passphrase,
+    unorm.nfkd(this.phrase),
+    unorm.nfkd('mnemonic' + this.passphrase),
     2048, 64);
 
   return this.seed;
@@ -196,7 +197,6 @@ Mnemonic.prototype.createMnemonic = function createMnemonic() {
  */
 
 Mnemonic.getWordlist = function getWordlist(lang) {
-  assert(lang === 'english', 'Unknown language.');
   switch (lang) {
     case 'simplified chinese':
       return require('../../etc/chinese-simplified.js');