# Mnemonic Code for HD Keys (BIP39)

As you have seen, generating HD keys is easy. However, what if we want an easy way to transmit such a key by telephone or hand writing?

Cold wallets like Trezor, generate the HD Keys from a sentence that can easily be written down. They call such a sentence “the seed” or “mnemonic”. And it can eventually be protected by a password or a PIN. ![](/files/-LL8tRwc_WbUqltY4dtK)

The language that you use to generate your 'easy to write' sentence is called a **Wordlist**.

![](/files/-LL8tRwe3lxxlQLIGsGo)

```csharp
Mnemonic mnemo = new Mnemonic(Wordlist.English, WordCount.Twelve);
ExtKey hdRoot = mnemo.DeriveExtKey("my password");
Console.WriteLine(mnemo);
```

`minute put grant neglect anxiety case globe win famous correct turn link`

Now, if you have the mnemonic and the password, you can recover the **hdRoot** key.

```csharp
mnemo = new Mnemonic("minute put grant neglect anxiety case globe win famous correct turn link",
                Wordlist.English);
hdRoot = mnemo.DeriveExtKey("my password");
```

Currently supported languages for **wordlist** are, English, Japanese, Spanish, Chinese (simplified and traditional).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://programmingblockchain.gitbook.io/programmingblockchain/key_generation/bip_39.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.