diff --git a/gulpfile.js b/gulpfile.js
index 86c9920f3..3f6cf318b 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -8,7 +8,7 @@ const replace = require("gulp-replace");
 const terser = require("gulp-terser");
 const cssnano = require("gulp-cssnano");
 
-const locales = require("./locales");
+const locales = require("./locales/legacy.cjs");
 const meta = require("./package.json");
 const customDir = process.env.ICESHRIMP_CUSTOM_DIR ?? "./custom";
 
diff --git a/locales/index.js b/locales/index.js
index 8a56c8663..09d3932f8 100644
--- a/locales/index.js
+++ b/locales/index.js
@@ -2,8 +2,8 @@
  * Languages Loader
  */
 
-const fs = require("fs");
-const yaml = require("js-yaml");
+import * as fs from 'node:fs';
+import * as yaml from 'js-yaml';
 const languages = [];
 const languages_custom = [];
 const customDir = process.env.ICESHRIMP_CUSTOM_DIR ?? __dirname + "/../custom";
diff --git a/locales/legacy.cjs b/locales/legacy.cjs
new file mode 100644
index 000000000..8a56c8663
--- /dev/null
+++ b/locales/legacy.cjs
@@ -0,0 +1,88 @@
+/**
+ * Languages Loader
+ */
+
+const fs = require("fs");
+const yaml = require("js-yaml");
+const languages = [];
+const languages_custom = [];
+const customDir = process.env.ICESHRIMP_CUSTOM_DIR ?? __dirname + "/../custom";
+
+const merge = (...args) =>
+	args.reduce(
+		(a, c) => ({
+			...a,
+			...c,
+			...Object.entries(a)
+				.filter(([k]) => c && typeof c[k] === "object")
+				.reduce((a, [k, v]) => ((a[k] = merge(v, c[k])), a), {}),
+		}),
+		{},
+	);
+
+fs.readdirSync(__dirname).forEach((file) => {
+	if (file.includes(".yml")) {
+		file = file.slice(0, file.indexOf("."));
+		languages.push(file);
+	}
+});
+
+fs.readdirSync(`${customDir}/locales`).forEach((file) => {
+	if (file.includes(".yml")) {
+		file = file.slice(0, file.indexOf("."));
+		languages_custom.push(file);
+	}
+});
+
+const primaries = {
+	en: "US",
+	ja: "JP",
+	zh: "CN",
+};
+
+// 何故か文字列にバックスペース文字が混入することがあり、YAMLが壊れるので取り除く
+const clean = (text) =>
+	text.replace(new RegExp(String.fromCodePoint(0x08), "g"), "");
+
+const locales = languages.reduce(
+	(a, c) => (
+		(a[c] =
+			yaml.load(clean(fs.readFileSync(`${__dirname}/${c}.yml`, "utf-8"))) ||
+			{}),
+		a
+	),
+	{},
+);
+const locales_custom = languages_custom.reduce(
+	(a, c) => (
+		(a[c] =
+			yaml.load(
+				clean(
+					fs.readFileSync(`${customDir}/locales/${c}.yml`, "utf-8"),
+				),
+			) || {}),
+		a
+	),
+	{},
+);
+Object.assign(locales, locales_custom);
+
+module.exports = Object.entries(locales).reduce(
+	(a, [k, v]) => (
+		(a[k] = (() => {
+			const [lang] = k.split("-");
+			switch (k) {
+				case "en-US":
+					return v;
+				default:
+					return merge(
+						locales["en-US"],
+						locales[`${lang}-${primaries[lang]}`] || {},
+						v,
+					);
+			}
+		})()),
+		a
+	),
+	{},
+);
diff --git a/packages/client/package.json b/packages/client/package.json
index 772dbe47a..92c55cb3c 100644
--- a/packages/client/package.json
+++ b/packages/client/package.json
@@ -9,6 +9,7 @@
 		"lint:vue": "paralint --ext .vue --fix '**/*.vue' --cache",
 		"format": "biome format * --write && prettier --write '**/*.{scss,vue}' --cache --cache-strategy metadata"
 	},
+	"type": "module",
 	"devDependencies": {
 		"@discordapp/twemoji": "14.1.2",
 		"@eslint-sets/eslint-config-vue3": "^5.6.1",
diff --git a/packages/sw/webpack.config.js b/packages/sw/webpack.config.js
index 8522eda3a..7e27464d1 100644
--- a/packages/sw/webpack.config.js
+++ b/packages/sw/webpack.config.js
@@ -1,6 +1,6 @@
 const webpack = require("webpack");
 const path = require("path");
-const locales = require("../../locales");
+const locales = require("../../locales/legacy.cjs");
 const meta = require("../../package.json");
 
 const isProduction = process.env.NODE_ENV === "production";