diff --git a/i18n.js b/i18n.js
index 00b81d3..e7faa61 100644
--- a/i18n.js
+++ b/i18n.js
@@ -17,6 +17,7 @@ const messages = {
     "nav.forks": "Fork",
     "nav.references": "참고문헌",
     "nav.work": "작업",
+    "nav.opensInNewTab": "(새 창에서 열림)",
     "nav.skipToContent": "본문으로 건너뛰기",
     "hero.title": "맥락지혜 연구실",
     "hero.labName": "Contextual Wisdom Lab",
@@ -164,6 +165,7 @@ const messages = {
     "nav.forks": "Forks",
     "nav.references": "References",
     "nav.work": "Work",
+    "nav.opensInNewTab": "(Opens in a new tab)",
     "nav.skipToContent": "Skip to main content",
     "hero.title": "Contextual Wisdom Lab",
     "hero.labName": "Research Lab",
@@ -312,6 +314,7 @@ function preferredLanguage() {
 
 // ⚡ Bolt: Cache DOM queries and current state to prevent redundant lookups and layout thrashing
 let i18nNodes = null;
+let i18nTitleNodes = null;
 let langButtons = null;
 let metaDesc = null;
 let ogDesc = null;
@@ -361,7 +364,7 @@ function setLanguage(lang) {
   }
 
   // ⚡ Bolt: 기본 언어로 초기 로드 시 불필요한 DOM 텍스트 읽기 및 탐색 생략 (성능 개선)
-  const isInitialDefault = lang === "ko" && !i18nNodes;
+  const isInitialDefault = lang === "ko" && !i18nNodes && !i18nTitleNodes;
 
   if (!isInitialDefault) {
     if (!i18nNodes) {
@@ -375,6 +378,16 @@ function setLanguage(lang) {
         node.textContent = newText;
       }
     });
+
+    if (!i18nTitleNodes) {
+      i18nTitleNodes = document.querySelectorAll("[data-i18n-title]");
+    }
+    i18nTitleNodes.forEach((node) => {
+      const newText = dict[node.dataset.i18nTitle];
+      if (newText && node.getAttribute("title") !== newText) {
+        node.setAttribute("title", newText);
+      }
+    });
   }
 
   langButtons.forEach((button) => {
diff --git a/index.html b/index.html
index a2dbbd7..02513ba 100644
--- a/index.html
+++ b/index.html
@@ -42,7 +42,7 @@
         <a href="#projects" data-i18n="nav.projects">프로젝트</a>
         <a href="#forks" data-i18n="nav.forks">Fork</a>
         <a href="#work" data-i18n="nav.work">작업</a>
-        <a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab">GitHub</a>
+        <a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">GitHub</a>
       </nav>
       <div class="language-switch" role="group" aria-label="Language">
         <button type="button" data-lang="ko" lang="ko" aria-pressed="true" aria-label="한국어">KO</button>
@@ -59,7 +59,7 @@ <h1 data-i18n="hero.title">맥락지혜 연구실</h1>
             구슬이 서 말이어도 꿰어야 보배이듯, 문서, 메일, 로그, 회의록을 맥락 안에서 엮어 사람이 무엇을 결정하고 무엇을 실행할지 보이게 하는 AI 의사결정 지원 시스템을 연구하고 만듭니다.
           </p>
           <div class="hero-actions" role="group" aria-label="Homepage actions">
-            <a target="_blank" rel="noopener noreferrer" class="button primary" href="https://github.com/ContextualWisdomLab" data-i18n="hero.primaryCta">GitHub 보기</a>
+            <a target="_blank" rel="noopener noreferrer" class="button primary" href="https://github.com/ContextualWisdomLab" data-i18n="hero.primaryCta" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">GitHub 보기</a>
             <a class="button secondary" href="#dikw" data-i18n="hero.secondaryCta">DIKW 보기</a>
           </div>
         </div>
@@ -254,19 +254,19 @@ <h2 data-i18n="references.title">참고문헌</h2>
         <ol class="reference-list">
           <li>
             <span data-i18n="references.ackoff">Ackoff, R. L. (1989). From data to wisdom. Journal of Applied Systems Analysis, 16(1), 3-9.</span>
-            <a target="_blank" rel="noopener noreferrer" href="https://faculty.ung.edu/kmelton/documents/datawisdom.pdf">https://faculty.ung.edu/kmelton/documents/datawisdom.pdf</a>
+            <a target="_blank" rel="noopener noreferrer" href="https://faculty.ung.edu/kmelton/documents/datawisdom.pdf" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">https://faculty.ung.edu/kmelton/documents/datawisdom.pdf</a>
           </li>
           <li>
             <span data-i18n="references.baskarada">Baskarada, S., &amp; Koronios, A. (2013). Data, information, knowledge, wisdom (DIKW): A semiotic theoretical and empirical exploration of the hierarchy and its quality dimension. Australasian Journal of Information Systems, 18(1).</span>
-            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.3127/ajis.v18i1.748">https://doi.org/10.3127/ajis.v18i1.748</a>
+            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.3127/ajis.v18i1.748" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">https://doi.org/10.3127/ajis.v18i1.748</a>
           </li>
           <li>
             <span data-i18n="references.fricke">Frické, M. (2009). The knowledge pyramid: A critique of the DIKW hierarchy. Journal of Information Science, 35(2), 131-142.</span>
-            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1177/0165551508094050">https://doi.org/10.1177/0165551508094050</a>
+            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1177/0165551508094050" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">https://doi.org/10.1177/0165551508094050</a>
           </li>
           <li>
             <span data-i18n="references.brienza">Brienza, J. P., Kung, F. Y. H., Santos, H. C., Bobocel, D. R., &amp; Grossmann, I. (2018). Wisdom, bias, and balance: Toward a process-sensitive measurement of wisdom-related cognition. Journal of Personality and Social Psychology, 115(6), 1093-1126.</span>
-            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1037/pspp0000171">https://doi.org/10.1037/pspp0000171</a>
+            <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1037/pspp0000171" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">https://doi.org/10.1037/pspp0000171</a>
           </li>
         </ol>
       </section>
@@ -327,39 +327,39 @@ <h2 data-i18n="projects.title">공개 프로젝트</h2>
         </div>
         <div class="naruon-grid project-grid">
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/naruon" data-i18n="projects.naruonTitle">Naruon</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/naruon" data-i18n="projects.naruonTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">Naruon</a></h3>
             <p data-i18n="projects.naruonBody">메일, 첨부, 일정, 작업을 맥락으로 묶어 판단과 실행으로 연결하는 AI 이메일 워크스페이스입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/pg-erd-cloud" data-i18n="projects.pgErdTitle">pg-erd-cloud</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/pg-erd-cloud" data-i18n="projects.pgErdTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">pg-erd-cloud</a></h3>
             <p data-i18n="projects.pgErdBody">PostgreSQL 스키마를 리버스 엔지니어링하고 ERD와 DDL 공유 흐름으로 관리하는 클라우드 MVP입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/bandscope" data-i18n="projects.bandscopeTitle">BandScope</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/bandscope" data-i18n="projects.bandscopeTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">BandScope</a></h3>
             <p data-i18n="projects.bandscopeBody">곡을 섹션, 역할, 템포, 연습 우선순위로 분석하는 로컬 우선 리허설 앱입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/codec-carver" data-i18n="projects.codecCarverTitle">codec-carver</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/codec-carver" data-i18n="projects.codecCarverTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">codec-carver</a></h3>
             <p data-i18n="projects.codecCarverBody">긴 녹음을 메타데이터를 보존한 FLAC/Opus 조각으로 변환하는 Python CLI입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/newsdom-api" data-i18n="projects.newsdomTitle">newsdom-api</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/newsdom-api" data-i18n="projects.newsdomTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">newsdom-api</a></h3>
             <p data-i18n="projects.newsdomBody">스캔된 일본어 신문 PDF를 기사, 제목, 본문, 이미지 구조의 DOM형 JSON으로 파싱하는 API입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/scopeweave" data-i18n="projects.scopeweaveTitle">scopeweave</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/scopeweave" data-i18n="projects.scopeweaveTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">scopeweave</a></h3>
             <p data-i18n="projects.scopeweaveBody">트리 편집, 진행률 계산, CSV/JSON, 주간 Gantt를 지원하는 정적 HTML/CSS/JS WBS 플래너입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/VibeSec" data-i18n="projects.vibesecTitle">VibeSec</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/VibeSec" data-i18n="projects.vibesecTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">VibeSec</a></h3>
             <p data-i18n="projects.vibesecBody">바이브코딩 앱을 위한 보안 가드레일입니다. AI 개발 도구 규칙, 정적 점검, 리뷰와 수정 프롬프트를 다룹니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/fast-mlsirm" data-i18n="projects.fastMlsirmTitle">fast-mlsirm</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/fast-mlsirm" data-i18n="projects.fastMlsirmTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">fast-mlsirm</a></h3>
             <p data-i18n="projects.fastMlsirmBody">MLSIRM/MLS2PLM 모형의 시뮬레이션, 적합, 복원 진단을 빠르게 수행하는 Python/Rust 패키지입니다.</p>
           </article>
           <article>
-            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/waf-ids-ai-soc" data-i18n="projects.wafIdsTitle">waf-ids-ai-soc</a></h3>
+            <h3><a target="_blank" rel="noopener noreferrer" href="https://github.com/ContextualWisdomLab/waf-ids-ai-soc" data-i18n="projects.wafIdsTitle" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">waf-ids-ai-soc</a></h3>
             <p data-i18n="projects.wafIdsBody">DNSBL 게시 기능을 갖춘 Rust 우선 WAF/IDS/AI SOC 게이트웨이입니다.</p>
           </article>
         </div>
@@ -431,7 +431,7 @@ <h2 data-i18n="work.title">연구에서 제품으로</h2>
       >
       <p>
         <span data-i18n="footer.founded">Founded by</span>
-        <a target="_blank" rel="noopener noreferrer" href="https://github.com/seonghobae">Seongho Bae</a>.
+        <a target="_blank" rel="noopener noreferrer" href="https://github.com/seonghobae" data-i18n-title="nav.opensInNewTab" title="(새 창에서 열림)">Seongho Bae</a>.
         <span data-i18n="footer.line">Context into judgment. Judgment into action.</span>
       </p>
     </footer>
diff --git a/tests/test_i18n_title.py b/tests/test_i18n_title.py
new file mode 100644
index 0000000..c4e4d3b
--- /dev/null
+++ b/tests/test_i18n_title.py
@@ -0,0 +1,10 @@
+"""Test i18n title functionality presence."""
+
+def test_i18n_title_query_selector_present() -> None:
+    """Test that data-i18n-title is queried correctly in i18n.js."""
+    with open("i18n.js", "r", encoding="utf-8") as f:
+        content = f.read()
+
+    assert "querySelectorAll(\"[data-i18n-title]\")" in content
+    assert "getAttribute(\"title\")" in content
+    assert "setAttribute(\"title\"" in content