diff --git a/src/node/markdown/markdown.ts b/src/node/markdown/markdown.ts
index 9cdaff85..a091639a 100644
--- a/src/node/markdown/markdown.ts
+++ b/src/node/markdown/markdown.ts
@@ -87,14 +87,25 @@ export interface MarkdownOptions extends Options {
    */
   languages?: (LanguageInput | BuiltinLanguage)[]
   /**
-   * Custom language aliases.
-   * Maps custom language names to existing languages for syntax highlighting.
-   * Language identifiers with underscores will automatically display with spaces.
-   * Alias lookup is case-insensitive.
+   * Custom language aliases for syntax highlighting.
+   * Maps custom language names to existing languages.
+   * Alias lookup is case-insensitive and underscores in language names are displayed as spaces.
    *
-   * @example { 'my_lang': 'python' } 
-   * 
-   * ```My_Lang uses Python highlighting, displays "My Lang"
+   * @example
+   *
+   * Maps `my_lang` to use Python syntax highlighting.
+   * ```js
+   * { 'my_lang': 'python' }
+   * ```
+   *
+   * Usage in markdown:
+   * ````md
+   * ```My_Lang
+   * # This will be highlighted as Python code
+   * # and will show "My Lang" as the language label
+   * print("Hello, World!")
+   * ```
+   * ````
    *
    * @see https://shiki.style/guide/load-lang#custom-language-aliases
    */
diff --git a/src/node/markdown/plugins/highlight.ts b/src/node/markdown/plugins/highlight.ts
index 4e62d3d1..780e37e8 100644
--- a/src/node/markdown/plugins/highlight.ts
+++ b/src/node/markdown/plugins/highlight.ts
@@ -68,10 +68,14 @@ export async function highlight(
       ...(options.languages || []),
       ...Object.values(options.languageAlias || {})
     ],
-    langAlias: options.languageAlias ?
-      Object.fromEntries(
-        Object.entries(options.languageAlias).map(([key, value]) => [key.toLowerCase(), value])
-      ) : undefined
+    langAlias: options.languageAlias
+      ? Object.fromEntries(
+          Object.entries(options.languageAlias).map(([key, value]) => [
+            key.toLowerCase(),
+            value
+          ])
+        )
+      : undefined
   })
 
   await options?.shikiSetup?.(highlighter)
diff --git a/src/node/markdown/plugins/preWrapper.ts b/src/node/markdown/plugins/preWrapper.ts
index d68043a1..38266509 100644
--- a/src/node/markdown/plugins/preWrapper.ts
+++ b/src/node/markdown/plugins/preWrapper.ts
@@ -18,7 +18,7 @@ export function preWrapperPlugin(md: MarkdownItAsync, options: Options) {
     token.info = token.info.replace(/ active$/, '').replace(/ active /, ' ')
 
     const lang = extractLang(token.info)
-    const langLabel = getLangLabel(lang, options.languageLabel)
+    const langLabel = options.languageLabel?.[lang] || lang.replace(/_/g, ' ')
 
     return (
       `<div class="language-${lang}${active}">` +
@@ -48,11 +48,3 @@ function extractLang(info: string) {
     .replace(/^vue-html$/, 'template')
     .replace(/^ansi$/, '')
 }
-
-function getLangLabel(lang: string, languageLabel?: Record<string, string>): string {
-  if (languageLabel && languageLabel[lang]) {
-    return languageLabel[lang]
-  }
-
-  return lang.replace(/_/g, ' ')
-}