diff --git a/bun.lockb b/bun.lockb
index 1eb9c18..b1afe10 100755
Binary files a/bun.lockb and b/bun.lockb differ
diff --git a/package.json b/package.json
index 34de339..d0a5356 100644
--- a/package.json
+++ b/package.json
@@ -16,9 +16,13 @@
   "dependencies": {
     "basic-styled": "^0.0.8",
     "firebase": "^10.14.0",
+    "i18next": "^23.16.6",
+    "i18next-browser-languagedetector": "^8.0.0",
+    "i18next-http-backend": "^2.6.2",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-helmet-async": "^2.0.5",
+    "react-i18next": "^15.1.1",
     "react-router-dom": "^6.26.2",
     "zustand": "^5.0.0-rc.2"
   },
diff --git a/public/locales/en/translation.json b/public/locales/en/translation.json
new file mode 100644
index 0000000..a57f87f
--- /dev/null
+++ b/public/locales/en/translation.json
@@ -0,0 +1,4 @@
+{
+  "title": "Plandy | Reminders & Calendar",
+  "intro_text": "Simple and easy task Manager"
+}
diff --git a/public/locales/ja/translation.json b/public/locales/ja/translation.json
new file mode 100644
index 0000000..602db17
--- /dev/null
+++ b/public/locales/ja/translation.json
@@ -0,0 +1,4 @@
+{
+  "title": "Plandy: \u30EA\u30DE\u30A4\u30F3\u30C0\u30FC\u0020\uFF06\u0020\u30AB\u30EC\u30F3\u30C0\u30FC",
+  "intro_text": "\u30B7\u30F3\u30D7\u30EB\u3067\u7C21\u5358\u306A\u30BF\u30B9\u30AF\u7BA1\u7406"
+}
diff --git a/public/locales/ko/translation.json b/public/locales/ko/translation.json
new file mode 100644
index 0000000..b3dfcd2
--- /dev/null
+++ b/public/locales/ko/translation.json
@@ -0,0 +1,4 @@
+{
+  "title": "Plandy | \uB9AC\uB9C8\uC778\uB354\u0020\u0026\u0020\uB2EC\uB825",
+  "intro_text": "\uBE60\uB974\uACE0\u0020\uAC04\uD3B8\uD55C\u0020\uC77C\uC815\uACFC\u0020\uD560\uC77C\u0020\uAD00\uB9AC"
+}
diff --git a/src/components/molecules/Header/Header.tsx b/src/components/molecules/Header/Header.tsx
index 3d8929d..3e9b5fa 100644
--- a/src/components/molecules/Header/Header.tsx
+++ b/src/components/molecules/Header/Header.tsx
@@ -9,6 +9,8 @@ import Select, { Option } from "@components/atoms/Select";
 import useThemeStore from "@stores/theme";
 import { GoogleAnalytics } from "@utils/google-analytics";
 
+import i18n from "@utils/i18n";
+
 import { Adornment, HeaderInner, Logo, StyledHeader } from "./Header.styles";
 
 function Header() {
@@ -16,7 +18,7 @@ function Header() {
   const updateTrigger = useThemeStore((state) => state.updateTrigger);
   const updateMode = useThemeStore((state) => state.updateMode);
 
-  const [language, setLanguage] = useState("english");
+  const [language, setLanguage] = useState(i18n.language);
 
   const handleClick = () => {
     updateTrigger("manual");
@@ -24,7 +26,10 @@ function Header() {
     handleLogEvent("theme");
   };
 
-  const handleChange = (newValue?: string) => setLanguage(newValue || "english");
+  const handleChangeLang = (newLang?: string) => {
+    i18n.changeLanguage(newLang);
+    setLanguage(newLang || "en");
+  };
 
   const handleLogEvent = (label: string) => {
     GoogleAnalytics.logEvent("click_top_nav", {
@@ -58,15 +63,18 @@ function Header() {
               data-testid="language-button"
               aria-label={language}
               size="small"
-              onChange={handleChange}
+              onChange={handleChangeLang}
               value={language}
               endIcon={<Icon name="ArrowDownBold" width={14} height={14} />}
             >
-              <Option data-testid="language-option-korea" value="korea">
+              <Option data-testid="language-option-english" value="en">
+                English
+              </Option>
+              <Option data-testid="language-option-korea" value="ko">
                 한국어
               </Option>
-              <Option data-testid="language-option-english" value="english">
-                English
+              <Option data-testid="language-option-japanese" value="ja">
+                日本語
               </Option>
             </Select>
             <Button
diff --git a/src/components/utils/GlobalStyle.tsx b/src/components/utils/GlobalStyle.tsx
index 1eb72db..c878487 100644
--- a/src/components/utils/GlobalStyle.tsx
+++ b/src/components/utils/GlobalStyle.tsx
@@ -47,6 +47,30 @@ const StyledGlobal = styled.style`
     flex-direction: column;
     min-height: 100%;
   }
+
+  @-webkit-keyframes bounceDelay {
+    0%,
+    80%,
+    100% {
+      -webkit-transform: scale(0);
+    }
+    40% {
+      -webkit-transform: scale(1);
+    }
+  }
+
+  @keyframes bounceDelay {
+    0%,
+    80%,
+    100% {
+      -webkit-transform: scale(0);
+      transform: scale(0);
+    }
+    40% {
+      -webkit-transform: scale(1);
+      transform: scale(1);
+    }
+  }
 `;
 
 export default GlobalStyle;
diff --git a/src/components/utils/Loading.tsx b/src/components/utils/Loading.tsx
new file mode 100644
index 0000000..7b1c3a1
--- /dev/null
+++ b/src/components/utils/Loading.tsx
@@ -0,0 +1,47 @@
+import styled from "basic-styled";
+
+function Loading() {
+  return (
+    <StyledSpinner>
+      <Bounce1 />
+      <Bounce2 />
+      <Bounce3 />
+    </StyledSpinner>
+  );
+}
+
+const StyledSpinner = styled.div`
+  display: flex;
+  justify-content: center;
+  gap: 20px;
+  width: 100%;
+  flex: 1 1 0;
+  transform: translateY(50%);
+
+  & > div {
+    width: 18px;
+    height: 18px;
+    background-color: ${({ theme: { palette } }) => palette.tertiary};
+    border-radius: 100%;
+    display: inline-block;
+    -webkit-animation: bounceDelay 1.4s infinite ease-in-out both;
+    animation: bounceDelay 1.4s infinite ease-in-out both;
+  }
+`;
+
+const Bounce1 = styled.div`
+  -webkit-animation-delay: -0.32s !important;
+  animation-delay: -0.32s !important;
+`;
+
+const Bounce2 = styled.div`
+  -webkit-animation-delay: -0.16s !important;
+  animation-delay: -0.16s !important;
+`;
+
+const Bounce3 = styled.div`
+  -webkit-animation-delay: -1.4s !important;
+  animation-delay: -1.4s !important;
+`;
+
+export default Loading;
diff --git a/src/main.tsx b/src/main.tsx
index 39723e1..3a1ab5e 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,10 +1,12 @@
-import { StrictMode } from "react";
+import { StrictMode, Suspense } from "react";
 
 import { HelmetProvider } from "react-helmet-async";
 import { BrowserRouter } from "react-router-dom";
+import "@utils/i18n";
 
-import ReactDOM from "react-dom/client";
+import { createRoot } from "react-dom/client";
 
+import Loading from "@components/utils/Loading";
 import ThemeProvider from "@providers/ThemeProvider";
 import { GoogleAnalytics } from "@utils/google-analytics";
 
@@ -12,14 +14,16 @@ import App from "./App";
 
 GoogleAnalytics.initialize();
 
-ReactDOM.createRoot(document.getElementById("root")!).render(
+createRoot(document.getElementById("root")!).render(
   <StrictMode>
-    <HelmetProvider>
-      <ThemeProvider>
-        <BrowserRouter>
-          <App />
-        </BrowserRouter>
-      </ThemeProvider>
-    </HelmetProvider>
+    <Suspense fallback={<Loading />}>
+      <HelmetProvider>
+        <ThemeProvider>
+          <BrowserRouter>
+            <App />
+          </BrowserRouter>
+        </ThemeProvider>
+      </HelmetProvider>
+    </Suspense>
   </StrictMode>
 );
diff --git a/src/pages/_components/Intro/Intro.tsx b/src/pages/_components/Intro/Intro.tsx
index 0682caf..8c048aa 100644
--- a/src/pages/_components/Intro/Intro.tsx
+++ b/src/pages/_components/Intro/Intro.tsx
@@ -1,3 +1,5 @@
+import { useTranslation } from "react-i18next";
+
 import Box from "@components/atoms/Box";
 import Button from "@components/atoms/Button";
 import Icon from "@components/atoms/Icon";
@@ -6,18 +8,18 @@ import Typography from "@components/atoms/Typography";
 import { ImageBox, StyledIntro, SubTitle, Title, TitleBox } from "./Intro.styles";
 
 function Intro() {
+  const { t } = useTranslation();
+
   return (
     <StyledIntro>
       <TitleBox>
         <Title>Plandy</Title>
-        <SubTitle>Simple schedule planner with Apple CloudKit</SubTitle>
+        <SubTitle>{t("intro_text")}</SubTitle>
         <Box mt={2}>
           <Button
             variant="text"
             startIcon={<Icon name="ImportBold" />}
-            onClick={() =>
-              window.open("https://apps.apple.com/us/app/plandy-reminders-calendar/id6736831438")
-            }
+            onClick={() => window.open("https://apps.apple.com/us/app/id6736831438")}
           >
             <Typography>Download On the</Typography>
             <Typography variant="title" fontWeight={700}>
diff --git a/src/utils/i18n.ts b/src/utils/i18n.ts
new file mode 100644
index 0000000..f63a982
--- /dev/null
+++ b/src/utils/i18n.ts
@@ -0,0 +1,35 @@
+import { initReactI18next } from "react-i18next";
+
+import i18n from "i18next";
+import LanguageDetector from "i18next-browser-languagedetector";
+import Backend from "i18next-http-backend";
+
+import translationEN from "../../public/locales/en/translation.json";
+import translationJA from "../../public/locales/ja/translation.json";
+import translationKO from "../../public/locales/ko/translation.json";
+
+export const resources = {
+  en: {
+    translation: translationEN
+  },
+  ko: {
+    translation: translationKO
+  },
+  ja: {
+    translation: translationJA
+  }
+};
+
+i18n
+  .use(Backend)
+  .use(LanguageDetector)
+  .use(initReactI18next)
+  .init({
+    resources,
+    fallbackLng: "en",
+    interpolation: {
+      escapeValue: false
+    }
+  });
+
+export default i18n;