diff --git a/src/App.tsx b/src/App.tsx
index 5b30b4a..0989bc3 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -9,7 +9,7 @@ export default function App() {
   const [sidebarOpen, setSidebarOpen] = useState(false);
 
   return (
-    <div className="h-dvh flex bg-[#1e1e24] text-zinc-300 bg-[radial-gradient(ellipse_at_top,rgba(255,255,255,0.02),transparent_50%),radial_gradient(ellipse_at_bottom_right,rgba(99,102,241,0.04),transparent_50%)]">
+    <div className="h-dvh flex bg-[#1e1e24] text-zinc-300 bg-[radial-gradient(ellipse_at_top,rgba(255,255,255,0.02),transparent_50%),radial_gradient(ellipse_at_bottom_right,rgba(99,102,241,0.04),transparent_50%)]" role="application" aria-label="PinchChat">
       <Sidebar
         sessions={sessions}
         activeSession={activeSession}
diff --git a/src/components/Chat.tsx b/src/components/Chat.tsx
index 8492bca..bba27aa 100644
--- a/src/components/Chat.tsx
+++ b/src/components/Chat.tsx
@@ -43,7 +43,7 @@ export function Chat({ messages, isGenerating, status, onSend, onAbort }: Props)
 
   return (
     <div className="flex-1 flex flex-col min-h-0">
-      <div className="flex-1 overflow-y-auto">
+      <div className="flex-1 overflow-y-auto" role="log" aria-label="Chat messages" aria-live="polite">
         <div className="max-w-4xl mx-auto py-4">
           {messages.length === 0 && (
             <div className="flex flex-col items-center justify-center h-[60vh] text-zinc-500">
@@ -54,7 +54,7 @@ export function Chat({ messages, isGenerating, status, onSend, onAbort }: Props)
                 </div>
               </div>
               <div className="text-lg text-zinc-200 font-semibold">PinchChat</div>
-              <div className="text-sm mt-1 text-zinc-500">Envoie un message pour commencer</div>
+              <div className="text-sm mt-1 text-zinc-500">Send a message to get started</div>
             </div>
           )}
           {messages.filter(hasVisibleContent).map(msg => (
diff --git a/src/components/ChatInput.tsx b/src/components/ChatInput.tsx
index e68f73c..7d5a1bd 100644
--- a/src/components/ChatInput.tsx
+++ b/src/components/ChatInput.tsx
@@ -179,6 +179,8 @@ export function ChatInput({ onSend, onAbort, isGenerating, disabled }: Props) {
   return (
     <div
       className="border-t border-white/8 bg-[#1a1a20]/60 backdrop-blur-xl p-4"
+      role="form"
+      aria-label="Message input"
       onDragOver={handleDragOver}
       onDragLeave={handleDragLeave}
       onDrop={handleDrop}
@@ -216,7 +218,8 @@ export function ChatInput({ onSend, onAbort, isGenerating, disabled }: Props) {
               onClick={() => fileInputRef.current?.click()}
               disabled={disabled}
               className="shrink-0 h-11 w-11 rounded-2xl border border-white/8 bg-zinc-800/30 flex items-center justify-center text-zinc-400 hover:text-cyan-300 hover:bg-white/5 transition-colors disabled:opacity-30"
-              title="Joindre un fichier"
+              title="Attach file"
+              aria-label="Attach file"
             >
               <Paperclip size={18} />
             </button>
@@ -235,7 +238,8 @@ export function ChatInput({ onSend, onAbort, isGenerating, disabled }: Props) {
               onChange={(e) => setText(e.target.value)}
               onKeyDown={handleKeyDown}
               onPaste={handlePaste}
-              placeholder="Écris un message…"
+              placeholder="Type a message…"
+              aria-label="Message"
               disabled={disabled}
               rows={1}
               className="flex-1 bg-transparent resize-none rounded-2xl border border-white/8 bg-zinc-900/35 px-4 py-3 text-sm text-zinc-300 placeholder:text-zinc-500 outline-none focus:ring-2 focus:ring-cyan-400/30 transition-all max-h-[200px]"
@@ -252,10 +256,11 @@ export function ChatInput({ onSend, onAbort, isGenerating, disabled }: Props) {
               <button
                 onClick={handleSubmit}
                 disabled={(!text.trim() && files.length === 0) || disabled}
+                aria-label="Send message"
                 className="shrink-0 h-11 px-5 rounded-2xl bg-gradient-to-r from-cyan-500/80 via-indigo-500/70 to-violet-500/80 text-zinc-900 font-semibold text-sm hover:opacity-90 shadow-[0_8px_24px_rgba(34,211,238,0.1)] disabled:opacity-30 disabled:shadow-none transition-all flex items-center gap-2"
               >
                 <Send size={16} />
-                <span className="hidden sm:inline">Envoyer</span>
+                <span className="hidden sm:inline">Send</span>
               </button>
             )}
           </div>
diff --git a/src/components/Header.tsx b/src/components/Header.tsx
index f3e34e9..7ce47cb 100644
--- a/src/components/Header.tsx
+++ b/src/components/Header.tsx
@@ -13,8 +13,8 @@ export function Header({ status, sessionKey, onToggleSidebar, activeSessionData
 
   return (
     <>
-    <header className="h-14 border-b border-white/8 bg-[#232329]/90 backdrop-blur-xl flex items-center px-4 gap-3 shrink-0">
-      <button onClick={onToggleSidebar} className="lg:hidden p-2 rounded-2xl hover:bg-white/5 text-zinc-400 transition-colors">
+    <header className="h-14 border-b border-white/8 bg-[#232329]/90 backdrop-blur-xl flex items-center px-4 gap-3 shrink-0" role="banner">
+      <button onClick={onToggleSidebar} aria-label="Toggle sidebar" className="lg:hidden p-2 rounded-2xl hover:bg-white/5 text-zinc-400 transition-colors">
         <Menu size={20} />
       </button>
       <div className="flex items-center gap-3 flex-1 min-w-0">
@@ -33,17 +33,17 @@ export function Header({ status, sessionKey, onToggleSidebar, activeSessionData
         {status === 'connected' ? (
           <div className="flex items-center gap-2 rounded-2xl border border-white/8 bg-zinc-800/30 px-3 py-1.5">
             <span className="w-2 h-2 rounded-full bg-cyan-300/80 shadow-[0_0_12px_rgba(34,211,238,0.6)]" />
-            <span className="text-xs text-zinc-300 hidden sm:inline">Connecté</span>
+            <span className="text-xs text-zinc-300 hidden sm:inline">Connected</span>
           </div>
         ) : status === 'connecting' ? (
           <div className="flex items-center gap-2 rounded-2xl border border-white/8 bg-zinc-800/30 px-3 py-1.5">
             <span className="w-2 h-2 rounded-full bg-yellow-400/80 pulse-dot" />
-            <span className="text-xs text-zinc-300 hidden sm:inline">Connexion…</span>
+            <span className="text-xs text-zinc-300 hidden sm:inline">Connecting…</span>
           </div>
         ) : (
           <div className="flex items-center gap-2 rounded-2xl border border-white/8 bg-zinc-800/30 px-3 py-1.5">
             <span className="w-2 h-2 rounded-full bg-red-400/80" />
-            <span className="text-xs text-zinc-300 hidden sm:inline">Déconnecté</span>
+            <span className="text-xs text-zinc-300 hidden sm:inline">Disconnected</span>
           </div>
         )}
       </div>
diff --git a/src/components/Sidebar.tsx b/src/components/Sidebar.tsx
index b66a37e..67a1ad6 100644
--- a/src/components/Sidebar.tsx
+++ b/src/components/Sidebar.tsx
@@ -13,7 +13,7 @@ export function Sidebar({ sessions, activeSession, onSwitch, open, onClose }: Pr
   return (
     <>
       {open && <div className="fixed inset-0 bg-black/60 backdrop-blur-sm z-40 lg:hidden" onClick={onClose} />}
-      <aside className={`fixed lg:relative top-0 left-0 h-full w-72 bg-[#1e1e24]/95 border-r border-white/8 z-50 transform transition-transform lg:translate-x-0 ${open ? 'translate-x-0' : '-translate-x-full'} flex flex-col backdrop-blur-xl`}>
+      <aside role="navigation" aria-label="Sessions" className={`fixed lg:relative top-0 left-0 h-full w-72 bg-[#1e1e24]/95 border-r border-white/8 z-50 transform transition-transform lg:translate-x-0 ${open ? 'translate-x-0' : '-translate-x-full'} flex flex-col backdrop-blur-xl`}>
         <div className="h-14 flex items-center justify-between px-4 border-b border-white/8">
           <div className="flex items-center gap-2">
             <div className="relative">
@@ -30,7 +30,7 @@ export function Sidebar({ sessions, activeSession, onSwitch, open, onClose }: Pr
         </div>
         <div className="flex-1 overflow-y-auto py-2 px-2">
           {sessions.length === 0 && (
-            <div className="px-3 py-8 text-center text-zinc-500 text-sm">Aucune session</div>
+            <div className="px-3 py-8 text-center text-zinc-500 text-sm">No sessions</div>
           )}
           {sessions.map(s => {
             const isActive = s.key === activeSession;
diff --git a/src/components/ThinkingBlock.tsx b/src/components/ThinkingBlock.tsx
index 917529c..94f33a9 100644
--- a/src/components/ThinkingBlock.tsx
+++ b/src/components/ThinkingBlock.tsx
@@ -11,7 +11,7 @@ export function ThinkingBlock({ text }: { text: string }) {
         className="inline-flex items-center gap-1.5 rounded-2xl border border-white/8 bg-zinc-800/35 px-3 py-1.5 text-xs text-violet-300 hover:bg-white/5 transition-colors"
       >
         <Brain size={13} />
-        <span className="font-medium">Réflexion</span>
+        <span className="font-medium">Thinking</span>
         {open ? <ChevronDown size={12} className="ml-1 text-zinc-500" /> : <ChevronRight size={12} className="ml-1 text-zinc-500" />}
       </button>
       {open && (
diff --git a/src/components/ToolCall.tsx b/src/components/ToolCall.tsx
index 62cc7b6..520dac7 100644
--- a/src/components/ToolCall.tsx
+++ b/src/components/ToolCall.tsx
@@ -188,7 +188,7 @@ export function ToolCall({ name, input, result }: { name: string; input?: any; r
           )}
           {result && (
             <div>
-              <div className={`text-[11px] ${c.text} opacity-70 mb-1 font-medium`}>Résultat</div>
+              <div className={`text-[11px] ${c.text} opacity-70 mb-1 font-medium`}>Result</div>
               <HighlightedPre
                 text={result}
                 className="text-xs bg-[#1a1a20]/60 border border-white/5 p-2.5 rounded-xl overflow-x-auto text-zinc-300 max-h-64 overflow-y-auto font-mono"