diff --git a/packages/polymech/src/app/config-loader.ts b/packages/polymech/src/app/config-loader.ts
index 0482957..beb471a 100644
--- a/packages/polymech/src/app/config-loader.ts
+++ b/packages/polymech/src/app/config-loader.ts
@@ -8,7 +8,7 @@ import { substitute } from "@polymech/commons/variables";
 import { appConfigSchema } from "./config.schema.js";
 import type { AppConfig } from "./config.schema.js";
 
-import { I18N_SOURCE_LANGUAGE } from "./constants.js"
+const I18N_SOURCE_LANGUAGE = 'en';
 
 const LIBRARY_CONFIG_PATH = path.resolve("./app-config.json");
 const USER_CONFIG_DEFAULT_PATH = path.resolve("./app-config.local.json");
@@ -51,8 +51,7 @@ export function loadConfig(
     }
 
     const variables = {
-        LANG: locale,
-        ...process.env
+        LANG: locale
     };
 
     const substitutedLibraryContent = substitute(false, rawLibraryContent, variables);
diff --git a/packages/polymech/src/app/config.ts b/packages/polymech/src/app/config.ts
index 52c3088..91a1545 100644
--- a/packages/polymech/src/app/config.ts
+++ b/packages/polymech/src/app/config.ts
@@ -4,10 +4,8 @@ import { resolve, template } from '@polymech/commons'
 import { sync as read } from '@polymech/fs/read'
 import { sanitizeUri } from 'micromark-util-sanitize-uri'
 import { loadConfig } from './config-loader.js'
-import { I18N_SOURCE_LANGUAGE } from "./constants.js"
-
-export { I18N_SOURCE_LANGUAGE }
 
+export const I18N_SOURCE_LANGUAGE = 'en'
 // Load config
 const config = loadConfig(I18N_SOURCE_LANGUAGE)
 
diff --git a/packages/polymech/src/app/network.ts b/packages/polymech/src/app/network.ts
index e92cc61..7d7cb5c 100644
--- a/packages/polymech/src/app/network.ts
+++ b/packages/polymech/src/app/network.ts
@@ -25,7 +25,7 @@ const imagesSchema = z.object({
 type Images = z.infer<typeof imagesSchema>;
 
 import { loadConfig } from './config-loader.js'
-import { I18N_SOURCE_LANGUAGE } from "./constants.js"
+import { I18N_SOURCE_LANGUAGE } from "./config.js"
 
 // Load config
 const config = loadConfig(I18N_SOURCE_LANGUAGE)