diff --git a/index.js b/index.js
index 8150106..edd442d 100644
--- a/index.js
+++ b/index.js
@@ -42,6 +42,16 @@ my.REGEXP_ALPHABET = {
   b64u: /^[A-Za-z0-9\-_]+$/,
   b64t: /^[A-Za-z0-9\._]+$/,
 }
+let lm = {}
+lm.chinese = lm.cn = lm.zh = lm.china = lm.zhcn = lm.chinese_simplified = 'chinese_simplified'
+lm.taiwanese = lm.tw = lm.zhtw = lm.chinese_traditional = 'chinese_traditional'
+lm.en = lm.us = lm.uk = lm.enus = lm.enlish = 'english'
+lm.fr = lm.france = lm.frfr = lm.french = 'french'
+lm.it = lm.italy = lm.itit = lm.italian = 'italian'
+lm.ko = lm.kr = lm.korean = lm.kokr = lm.koren = 'korean'
+lm.ja = lm.jp = lm.japan = lm.jajp = lm.japanese = 'japanese'
+lm.es = lm.eses = lm.spanish = 'spanish'
+my.langMap = lm
 
 /**
  *
@@ -99,20 +109,26 @@ class TicCrypto {
    * @return {Boolean}
    * @memberof TicCrypto
    */
-  static is_secword ({ secword, mode = 'strict' } = {}) {
-    // 注意 not all 12 words combinations are valid for both bitcore and bip39, because there are checksum in mnemonic. 另外，实际上bitcore和bip39对12, 15, 18, 21, 24 长度的合法助记词都返回 true。
+  static is_secword ({ secword, mode = 'strict', lang } = {}) {
+    // 注意 not all 12 words combinations are valid for both bitcore and bip39, because there are checksum in mnemonic. 另外，实际上bitcore和bip39对 12, 15, 18, 21, 24 长度的合法助记词都返回 true。
+
     //// for bitcore-mnemonic. 注意，bitcore-mnemonic 对少于12词的会抛出异常，很蠢。
-    // if (typeof secword==='string' && 12===secword.split(/ +/).length)
+    // if (typeof secword==='string' && [12,15,18,21,24].includes(secword.split(/ +/).length))
     //   return BitcoreMnemonic.isValid(secword)
     // else
     //   return false
 
     //// for bip39. 注意，bip39对当前defaultWordlist之外其他语言的合法 mnemonic 也返回 false，这一点不如 bitcore-mnemonic. 所以不能直接 bip39.validateMnemonic(secword)
-    if (typeof secword === 'string' && !/(^\s)|\s\s|(\s$)/.test(secword) && 12 === secword.split(/\s+/).length) {
-      if (mode === 'easy') return true // easy模式不检查校验等等严格的合法性了，反正 secword2seed是接受一切字符串的
-      for (let lang of Object.keys(bip39.wordlists)) {
-        bip39.setDefaultWordlist(lang)
-        if (bip39.validateMnemonic(secword)) return true
+    if (typeof secword === 'string' && !/(^\s)|\s\s|(\s$)/.test(secword) && [12, 15, 18, 21, 24].includes(secword.split(/\s+/).length)) {
+      if (mode === 'easy') return true // easy模式不检查校验等等严格的合法性了，反正 secword_to_seed 是接受一切字符串的
+      if (my.langMap[lang?.toLowerCase()]) {
+        // 指定了语言则针对该语言词库检查
+        return bip39.validateMnemonic(secword, bip39.wordlists[my.langMap[lang?.toLowerCase()]])
+      } else {
+        // 未指定语言则检查所有可能语言词库
+        for (let lang of Object.keys(bip39.wordlists)) {
+          return bip39.validateMnemonic(secword, bip39.wordlists[my.langMap[lang?.toLowerCase()]])
+        }
       }
     }
     return false
@@ -359,7 +375,7 @@ class TicCrypto {
    * @return {Object} {pubkey, seckey, address,}
    * @memberof TicCrypto
    */
-  static pass2keypair ({ pass, hasher } = {}) {
+  static pass_to_keypair ({ pass, hasher } = {}) {
     // 如果使用其他机制，例如密码、随机数，不使用secword，也可生成keypair
     if (this.is_hashable({ data: pass })) {
       hasher = my.HASHER_LIST.includes(hasher) ? hasher : my.HASHER
@@ -398,9 +414,14 @@ class TicCrypto {
    * @return {*}
    * @memberof TicCrypto
    */
-  static secword_to_entropy ({ secword } = {}) {
+  static secword_to_entropy ({ secword, lang } = {}) {
     // secword could be of length 12|15|18|21|24，which outputs hex of length 32|40|48|56|64.
-    return bip39.mnemonicToEntropy(secword) // results are the same for the same secword.
+    try {
+      return bip39.mnemonicToEntropy(secword, bip39.wordlists[my.langMap[lang?.toLowerCase()] || 'english']) // results are the same for the same secword
+    } catch (exception) {
+      // 如果助记词不合法（例如，语言不符合，长度非法，校验码不正确），会抛出异常。
+      return ''
+    }
   }
 
   /**
@@ -836,6 +857,7 @@ class TicCrypto {
 
   /**
    * 生成随机的助记词
+   * accepts case-insensitive lang, such as 'chinese, cn, tw, en'
    * 1) 生成 128、160、192、224、256 位的随机墒
    * 2）sha256 取前 墒长度/32 位作为校验和，即可为 4、5、6、7、8 位
    * 3）在2048（=2^11）个词的表中，每11位指向一个词，共可生成 (128+4)/11=12, (160+5)/11=15, (192+6)/11=18, (224+7)/11=21, (256+8)/11=24 个词
@@ -845,8 +867,7 @@ class TicCrypto {
    * @return {*}
    * @memberof TicCrypto
    */
-  static randomize_secword ({ lang = 'english', wordCount = 12 } = {}) {
-    // accepts case-insensitive lang, such as 'chinese, cn, tw, en'
+  static randomize_secword ({ lang, wordCount = 12 } = {}) {
     //// for BitcoreMnemonic
     // lang=lang?.toUpperCase()
     // let language = { ZHCN: 'CHINESE', ENUS: 'ENGLISH', FRFR: 'FRENCH', ITIT: 'ITALIAN', JAJP: 'JAPANESE', KOKR: 'KOREAN', ESES: 'SPANISH' }[lang]
@@ -855,31 +876,8 @@ class TicCrypto {
 
     // for bip39
     const bitLength = { 12: 128, 15: 160, 18: 192, 21: 224, 24: 256 }[wordCount] || 128
-
-    const langMap = {
-      zhcn: 'chinese_simplified',
-      zhtw: 'chinese_traditional',
-      enus: 'english',
-      frfr: 'french',
-      itit: 'italian',
-      jajp: 'japanese',
-      kokr: 'korean',
-      eses: 'spanish',
-    }
-    langMap.chinese = langMap.cn = langMap.zh = langMap.china = langMap.zhcn
-    langMap.taiwanese = langMap.tw = langMap.zhtw
-    langMap.en = langMap.us = langMap.uk = langMap.enus
-    langMap.fr = langMap.france = langMap.frfr
-    langMap.it = langMap.italy = langMap.itit
-    langMap.ko = langMap.kr = langMap.korean = langMap.kokr
-    langMap.ja = langMap.jp = langMap.japan = langMap.jajp
-    let language = 'english'
-    if (typeof lang === 'string') {
-      lang = lang.toLowerCase()
-      language = langMap[lang] || (bip39.wordlists[lang] ? lang : 'english')
-    }
-    // bip39.setDefaultWordlist(language)
-    return bip39.generateMnemonic(bitLength, undefined, bip39.wordlists[language]) // 内部使用 crypto.randomBytes 来获取随机墒
+    // bip39.setDefaultWordlist(langMap[lang?.toLowerCase()] || 'english')
+    return bip39.generateMnemonic(bitLength, undefined, bip39.wordlists[my.langMap[lang?.toLowerCase()] || 'english']) // 内部使用 crypto.randomBytes 来获取随机墒
   }
 
   /**