diff --git a/Makefile b/Makefile
index 1feb0a44e36..7997ac53d45 100644
--- a/Makefile
+++ b/Makefile
@@ -58,7 +58,13 @@ dev:
 	@echo "Starting development servers..."
 	@# Start both processes, with marimo in background
 	@(trap 'kill %1; exit' INT; \
-	marimo edit --no-token --headless /tmp & \
+	uv run marimo edit --no-token --headless /tmp & \
+	pnpm dev)
+dev-sandbox:
+	@echo "Starting development servers..."
+	@# Start both processes, with marimo in background
+	@(trap 'kill %1; exit' INT; \
+	uv run marimo edit /tmp/notebook.py --no-token --headless --sandbox & \
 	pnpm dev)
 
 #############
diff --git a/frontend/src/components/app-config/user-config-form.tsx b/frontend/src/components/app-config/user-config-form.tsx
index f344fbe1559..5a3c6496900 100644
--- a/frontend/src/components/app-config/user-config-form.tsx
+++ b/frontend/src/components/app-config/user-config-form.tsx
@@ -13,6 +13,7 @@ import {
   PackageIcon,
 } from "lucide-react";
 import React, { useId, useRef } from "react";
+import { useLocale } from "react-aria";
 import { useForm } from "react-hook-form";
 import { Button } from "@/components/ui/button";
 import { Checkbox } from "@/components/ui/checkbox";
@@ -118,6 +119,7 @@ export const UserConfigForm: React.FC = () => {
   );
   const capabilities = useAtomValue(capabilitiesAtom);
   const marimoVersion = useAtomValue(marimoVersionAtom);
+  const { locale } = useLocale();
   const { saveUserConfig } = useRequestClient();
 
   // Create form
@@ -1333,8 +1335,9 @@ export const UserConfigForm: React.FC = () => {
               </TabsTrigger>
             ))}
 
-            <div className="p-2 text-xs text-muted-foreground self-start">
+            <div className="p-2 text-xs text-muted-foreground self-start flex flex-col gap-1">
               <span>Version: {marimoVersion}</span>
+              <span>Locale: {locale}</span>
             </div>
 
             <div className="flex-1" />
diff --git a/frontend/src/core/i18n/local-provider.tsx b/frontend/src/core/i18n/local-provider.tsx
new file mode 100644
index 00000000000..f77162dc433
--- /dev/null
+++ b/frontend/src/core/i18n/local-provider.tsx
@@ -0,0 +1,12 @@
+/* Copyright 2024 Marimo. All rights reserved. */
+
+import type { ReactNode } from "react";
+import { I18nProvider } from "react-aria-components";
+
+interface LocaleProviderProps {
+  children: ReactNode;
+}
+
+export const LocaleProvider = ({ children }: LocaleProviderProps) => {
+  return <I18nProvider>{children}</I18nProvider>;
+};
diff --git a/frontend/src/core/islands/components/web-components.tsx b/frontend/src/core/islands/components/web-components.tsx
index ef0ae98e92e..db5075b227a 100644
--- a/frontend/src/core/islands/components/web-components.tsx
+++ b/frontend/src/core/islands/components/web-components.tsx
@@ -7,6 +7,7 @@ import { ErrorBoundary } from "@/components/editor/boundary/ErrorBoundary";
 import { TooltipProvider } from "@/components/ui/tooltip";
 import { notebookAtom } from "@/core/cells/cells";
 import { UI_ELEMENT_REGISTRY } from "@/core/dom/uiregistry";
+import { LocaleProvider } from "@/core/i18n/local-provider";
 import { renderHTML } from "@/plugins/core/RenderHTML";
 import { invariant } from "@/utils/invariant";
 import type { CellId } from "../../cells/ids";
@@ -80,16 +81,18 @@ export class MarimoIslandElement extends HTMLElement {
     this.root?.render(
       <ErrorBoundary>
         <Provider store={store}>
-          <TooltipProvider>
-            <MarimoOutputWrapper
-              cellId={this.cellId}
-              codeCallback={codeCallback}
-              alwaysShowRun={alwaysShowRun}
-            >
-              {initialHtml}
-            </MarimoOutputWrapper>
-            {editor}
-          </TooltipProvider>
+          <LocaleProvider>
+            <TooltipProvider>
+              <MarimoOutputWrapper
+                cellId={this.cellId}
+                codeCallback={codeCallback}
+                alwaysShowRun={alwaysShowRun}
+              >
+                {initialHtml}
+              </MarimoOutputWrapper>
+              {editor}
+            </TooltipProvider>
+          </LocaleProvider>
         </Provider>
       </ErrorBoundary>,
     );
diff --git a/frontend/src/mount.tsx b/frontend/src/mount.tsx
index 59fe1db2b9e..8a0f2964e9a 100644
--- a/frontend/src/mount.tsx
+++ b/frontend/src/mount.tsx
@@ -26,6 +26,7 @@ import {
   parseConfigOverrides,
   parseUserConfig,
 } from "./core/config/config-schema";
+import { LocaleProvider } from "./core/i18n/local-provider";
 import { MarimoApp, preloadPage } from "./core/MarimoApp";
 import { type AppMode, initialModeAtom, viewStateAtom } from "./core/mode";
 import { cleanupAuthQueryParams } from "./core/network/auth";
@@ -82,9 +83,11 @@ export function mount(options: unknown, el: Element): Error | undefined {
 
     root.render(
       <Provider store={store}>
-        <ThemeProvider>
-          <MarimoApp />
-        </ThemeProvider>
+        <LocaleProvider>
+          <ThemeProvider>
+            <MarimoApp />
+          </ThemeProvider>
+        </LocaleProvider>
       </Provider>,
     );
   } catch (error) {
diff --git a/frontend/src/plugins/core/registerReactComponent.tsx b/frontend/src/plugins/core/registerReactComponent.tsx
index cb1f4d2f353..868a9671c57 100644
--- a/frontend/src/plugins/core/registerReactComponent.tsx
+++ b/frontend/src/plugins/core/registerReactComponent.tsx
@@ -29,6 +29,7 @@ import { createInputEvent, MarimoValueUpdateEvent } from "@/core/dom/events";
 import { getUIElementObjectId } from "@/core/dom/ui-element";
 import { UIElementRegistry } from "@/core/dom/uiregistry";
 import { FUNCTIONS_REGISTRY } from "@/core/functions/FunctionRegistry";
+import { LocaleProvider } from "@/core/i18n/local-provider";
 import { store } from "@/core/state/jotai";
 import {
   type HTMLElementNotDerivedFromRef,
@@ -363,16 +364,18 @@ export function registerReactComponent<T>(plugin: IPlugin<T, unknown>): void {
 
       invariant(this.root, "Root must be defined");
       this.root.render(
-        <PluginSlot
-          hostElement={this}
-          plugin={plugin}
-          ref={this.pluginRef}
-          getInitialValue={() => {
-            return parseInitialValue(this, UIElementRegistry.INSTANCE);
-          }}
-        >
-          {this.getChildren()}
-        </PluginSlot>,
+        <LocaleProvider>
+          <PluginSlot
+            hostElement={this}
+            plugin={plugin}
+            ref={this.pluginRef}
+            getInitialValue={() => {
+              return parseInitialValue(this, UIElementRegistry.INSTANCE);
+            }}
+          >
+            {this.getChildren()}
+          </PluginSlot>
+        </LocaleProvider>,
       );
     }
 
diff --git a/marimo/_cli/envinfo.py b/marimo/_cli/envinfo.py
index 15f06d98a6c..210e8873326 100644
--- a/marimo/_cli/envinfo.py
+++ b/marimo/_cli/envinfo.py
@@ -46,6 +46,16 @@ def get_experimental_flags() -> dict[str, Union[str, bool, dict[str, Any]]]:
         return {}
 
 
+def get_default_locale() -> str:
+    try:
+        import locale
+
+        default_locale, _ = locale.getdefaultlocale()
+        return default_locale or "--"
+    except Exception:
+        return "--"
+
+
 def get_system_info() -> dict[str, Union[str, bool, dict[str, Any]]]:
     os_version = platform.release()
     if platform.system() == "Windows" and is_win11():
@@ -61,6 +71,7 @@ def get_system_info() -> dict[str, Union[str, bool, dict[str, Any]]]:
         # e.g., x86 or arm
         "Processor": platform.processor(),
         "Python Version": platform.python_version(),
+        "Locale": get_default_locale(),
     }
 
     binaries = {