ltex: added ltex change language tipps

wiki/docker/alexta69_-_metube.md

@@ -32,7 +32,7 @@ Set the following ports in the `ports:` section.
 ```sh
 #!/bin/sh
 docker-compose down
-docker pull vim alexta69/metube
+docker pull alexta69/metube
 docker-compose up -d
 ```
 

wiki/ltex.md

@@ -0,0 +1,81 @@
+# LTeX
+
+[LTeX](https://valentjn.github.io/ltex/index.html) is an offline grammar checking tool that can use
+the Language Server Protocol - short LSP.
+It is supports various [Markup languages](/wiki/markup_language.md) like LaTeX and Markdown.
+
+## Setup
+
+LTeX can be installed on various editors and officially supports VS Code, Vim and Neovim.
+For Neovim the completion tool `coc` is recommended, but Neovims own lspconfig can be used aswell.
+
+## Usage
+
+This section addresses the usage of LTeX.
+
+### Switching Languages Inside a File
+
+The language is normally static for all file types.
+It can however be changed using magic comments as explained in
+[the official documentation](https://valentjn.github.io/ltex/advanced-usage.html].
+
+### Switching Languages in Markdown
+
+At the start of a file the following lines - called YAML front matter - can be used to change the
+language for the whole file.
+In the following it is changed to german (`de-DE`) but this can be changed.
+
+```md
+---
+lang: de-DE
+---
+```
+
+The following magic comment can be used to change the language from the place of the comment
+onwards.
+
+```md
+<!-- LTeX: language=de-DE -->
+```
+
+### Switching Languages in LaTeX
+
+The following magic comment can be used to change the language from the place of the comment
+onwards.
+
+```tex
+% LTeX: language=de-DE
+```
+
+However this can be difficult when only using a few words.
+Another easy and generally recommended way to change the language inside LaTeX documents is using
+the babel package.
+In the following examples `<language>` is the language indicator that babel uses (for example
+`english`, `american`, `ngerman`).
+
+At the start of the document the language can be changed for the rest of the file using the
+following command.
+
+```tex
+\usepackage[<language>]{babel}
+```
+
+Additionally the following command can be used to change the language from that place onwards.
+
+```tex
+\selectlanguage{<language>}
+```
+
+Using the following command the language can be changed just for the text that is subsituted for
+`<text>`.
+
+```
+\foreignlanguage{<language>}{<text>}
+```
+
+Finally an otherlanguage environment can be used to achieve the same as shown in the following
+example.
+
+```tex
+\begin{otherlanguage}{<language>}<text>\end{otherlanguage}
+```

wiki/markup_language.md

@@ -3,7 +3,16 @@
 A markup Language is way to encode text so that it has great amounts of structure and formatting.
 The most common markup languages are [HTML](#html), Markdown, LaTeX and [XML](#xml).
 
-## HTML
+## Grammar Checking
+
+An often used grammar and spell checking tool that supports many markup languages is
+[LTeX](/wiki/ltex.md).
+
+## Different languages
+
+This section addresses various markup languages and their usages.
+
+### HTML
 
 HTML is a markup language that is mostly used in the internet via the hypertext system and accessed
 via [web browsers](/wiki/web_browser.md).
@@ -13,6 +22,6 @@ An easy way to do the latter one is a validation service.
 One of the most used ones is the
 [Markup Validation Service by W3C](https://validator.w3.org/#validate_by_input).
 
-## XML
+### XML
 
 XML is a markup language often used together with [RSS Feeds](/wiki/rss.md).