@@ -62,6 +62,12 @@ describe('Redirect Tests', () => {
     expect(res.headers.location).toBe('/api/pagelist/en/free-pro-team@latest')
   })
 
+  test('redirects a plan name without a version to English', async () => {
+    const res = await get('/api/pagelist/free-pro-team')
+    expect(res.statusCode).toBe(308)
+    expect(res.headers.location).toBe('/api/pagelist/en/free-pro-team@latest')
+  })
+
   test('should redirect to /pagelist/en/free-pro-team@lateset when URL does not include version', async () => {
     const res = await get('/api/pagelist/en')
     expect(res.statusCode).toBe(308)
 
@@ -16,7 +16,7 @@ export const getEnterpriseVersionNumber = /enterprise\/(\d+\.\d+(?:\.340)?)/
 export const removeEnterpriseVersion = /(enterprise\/)\d+\.\d+\//
 export const guides = /guides\//
 export const hasLanguageCode = /^\/[a-z]{2}(\/|$|\?)/
-export const getLanguageCode = /^\/([a-z]{2})/
+export const getLanguageCode = /^\/([a-z]{2})(?=\/|$|\?)/
 export const trailingSlash = /^(.+?)\/+?$/
 export const searchPath = /\/search(?:\/)?(\?)/
 export const ymd = /^\d{4}-\d{2}-\d{2}$/
 
@@ -1,6 +1,25 @@
 import { describe, expect, test } from 'vitest'
 
-import { getProductStringFromPath } from '@/frame/lib/path-utils'
+import { getLangFromPath, getProductStringFromPath } from '@/frame/lib/path-utils'
+
+describe('getLangFromPath', () => {
+  test('returns null when the first segment is not a language code', () => {
+    expect(getLangFromPath('/free-pro-team')).toBeNull()
+    expect(getLangFromPath('/free-pro-team@latest')).toBeNull()
+    expect(getLangFromPath('/enterprise-cloud')).toBeNull()
+    expect(getLangFromPath('/enterprise-server')).toBeNull()
+    expect(getLangFromPath('/github/foo')).toBeNull()
+  })
+
+  test('returns the language code from the first segment', () => {
+    expect(getLangFromPath('/en')).toBe('en')
+    expect(getLangFromPath('/fr')).toBe('fr')
+    expect(getLangFromPath('/en?x=1')).toBe('en')
+    expect(getLangFromPath('/fr/free-pro-team')).toBe('fr')
+    expect(getLangFromPath('/fr/free-pro-team@latest')).toBe('fr')
+    expect(getLangFromPath('/ja/enterprise-server@3.19')).toBe('ja')
+  })
+})
 
 describe('getProductStringFromPath', () => {
   test('returns "homepage" for root paths', () => {