Docs: Added instructions on cross-language search (#7812)

### What problem does this PR solve?



### Type of change


- [x] Documentation Update

docs/guides/chat/start_chat.md

@@ -42,6 +42,10 @@ You start an AI conversation by creating an assistant.
    - **Rerank model** sets the reranker model to use. It is left empty by default.
      - If **Rerank model** is left empty, the hybrid score system uses keyword similarity and vector similarity, and the default weight assigned to the vector similarity component is 1-0.7=0.3.
      - If **Rerank model** is selected, the hybrid score system uses keyword similarity and reranker score, and the default weight assigned to the reranker score is 1-0.7=0.3.
+   - **Cross-language search**: Optional  
+     Select one or more target languages from the dropdown menu. The system’s default chat model will then translate your query into the selected target language(s). This translation ensures accurate semantic matching across languages, allowing you to retrieve relevant results regardless of language differences.  
+     - When selecting target languages, please ensure that these languages are present in the knowledge base to guarantee an effective search.
+     - If no target language is selected, the system will search only in the language of your query, which may cause relevant information in other languages to be missed.
    - **Variable** refers to the variables (keys) to be used in the system prompt. `{knowledge}` is a reserved variable. Click **Add** to add more variables for the system prompt.
       - If you are uncertain about the logic behind **Variable**, leave it *as-is*.
       - As of v0.18.0, if you add custom variables here, the only way you can pass in their values is to call:

docs/guides/dataset/configure_knowledge_base.md

@@ -67,6 +67,10 @@ The following embedding models can be deployed locally:
 - BAAI/bge-large-zh-v1.5
 - maidalun1020/bce-embedding-base_v1
 
+:::danger IMPORTANT
+Please note these two embedding models support both English and Chinese. If your knowledge base contains other languages, the performance may be COMPROMISED.
+:::
+
 ### Upload file
 
 - RAGFlow's **File Management** allows you to link a file to multiple knowledge bases, in which case each target knowledge base holds a reference to the file.

docs/guides/dataset/run_retrieval_test.md

@@ -60,6 +60,15 @@ The switch is disabled by default. When enabled, RAGFlow performs the following
 Using a knowledge graph in a retrieval test will significantly increase the time to receive a response.
 :::
 
+### Cross-language search
+
+To perform a cross-language search, select one or more target languages from the dropdown menu. The system’s default chat model will then translate your query entered in the Test text field into the selected target language(s). This translation ensures accurate semantic matching across languages, allowing you to retrieve relevant results regardless of language differences.
+
+:::tip NOTE
+- When selecting target languages, please ensure that these languages are present in the knowledge base to guarantee an effective search.
+- If no target language is selected, the system will search only in the language of your query, which may cause relevant information in other languages to be missed.
+:::
+
 ### Test text
 
 This field is where you put in your testing query.

docs/quickstart.mdx

@@ -205,7 +205,7 @@ This section provides instructions on setting up the RAGFlow server on Linux. If
 <APITable>
 ```
 
-| RAGFlow image tag   | Image size (GB) | Has embedding models and Python packages? | Stable?                  |
+| RAGFlow image tag   | Image size (GB) | Has embedding models and Python packages?:collision: | Stable?                  |
 | ------------------- | --------------- | ----------------------------------------- | ------------------------ |
 | `v0.18.0`           | &approx;9       | :heavy_check_mark:                        | Stable release           |
 | `v0.18.0-slim`      | &approx;2       | ❌                                        | Stable release           |
@@ -216,6 +216,15 @@ This section provides instructions on setting up the RAGFlow server on Linux. If
 </APITable>
 ```
 
+:::danger IMPORTANT
+:collision: The embedding models included in `v0.18.0` and `nightly` are:
+
+- BAAI/bge-large-zh-v1.5
+- maidalun1020/bce-embedding-base_v1
+
+Please note these two embedding models support both English and Chinese. If your knowledge base contains other languages, the performance may be COMPROMISED.
+:::
+
 4. Check the server status after having the server up and running:
 
    ```bash

docs/references/glossary.mdx

@@ -0,0 +1,26 @@
+---
+sidebar_position: 0
+slug: /glossary
+---
+
+# Glossary
+
+Definitions of key terms and basic concepts related to RAGFlow.
+
+---
+
+import TOCInline from '@theme/TOCInline';
+
+<TOCInline toc={toc} />
+
+---
+
+## C
+
+### Cross-language search
+
+Cross-language search (also known as cross-lingual retrieval) is a feature introduced in version 0.19.0. It enables users to submit queries in one language (for example, English) and retrieve relevant documents written in other languages such as Chinese or Spanish. This feature is enabled by the system’s default chat model, which translates queries to ensure accurate matching of semantic meaning across languages.
+
+By enabling cross-language search, users can effortlessly access a broader range of information regardless of language barriers, significantly enhancing the system’s usability and inclusiveness.
+
+This feature is available in the retrieval test and chat assistant settings. See [Run retrieval test](../guides/dataset/run_retrieval_test.md) and [Start AI chat](../guides/chat/start_chat.md) for further details.

docs/references/http_api_reference.md

@@ -1,5 +1,5 @@
 ---
-sidebar_position: 1
+sidebar_position: 4
 slug: /http_api_reference
 ---
 

docs/references/python_api_reference.md

@@ -1,5 +1,5 @@
 ---
-sidebar_position: 2
+sidebar_position: 5
 slug: /python_api_reference
 ---
 

docs/references/supported_models.mdx

@@ -1,5 +1,5 @@
 ---
-sidebar_position: 0
+sidebar_position: 1
 slug: /supported_models
 ---