diff --git a/src/document.ts b/src/document.ts
index f941f258..c1b96046 100644
--- a/src/document.ts
+++ b/src/document.ts
@@ -5,10 +5,12 @@
  * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
  */
 
+import { extname } from 'node:path';
 import { URI } from 'vscode-uri';
 import * as lsp from 'vscode-languageserver';
 import { TextDocument } from 'vscode-languageserver-textdocument';
 import * as languageModeIds from './configuration/languageIds.js';
+import { LspClient } from './lsp-client.js';
 import { CommandTypes, type ts } from './ts-protocol.js';
 import { ClientCapability, type ITypeScriptServiceClient } from './typescriptService.js';
 import API from './utils/api.js';
@@ -26,6 +28,24 @@ function mode2ScriptKind(mode: string): ts.server.protocol.ScriptKindName | unde
     return undefined;
 }
 
+/**
+ * @deprecated Remove in next major.
+ */
+function getModeFromFileUri(uri: string): string | undefined {
+    const extension = extname(uri).toUpperCase();
+    switch (extension) {
+        case '.TS':
+            return languageModeIds.typescript;
+        case '.TSX':
+            return languageModeIds.typescriptreact;
+        case '.JS':
+            return languageModeIds.javascript;
+        case '.JSX':
+            return languageModeIds.javascriptreact;
+    }
+    return undefined;
+}
+
 class PendingDiagnostics extends ResourceMap<number> {
     public getOrderedFileSet(): ResourceMap<void> {
         const orderedResources = Array.from(this.entries())
@@ -203,6 +223,7 @@ export class LspDocument {
 
 export class LspDocuments {
     private readonly client: ITypeScriptServiceClient;
+    private readonly lspClient: LspClient;
 
     private _validateJavaScript = true;
     private _validateTypeScript = true;
@@ -216,9 +237,11 @@ export class LspDocuments {
 
     constructor(
         client: ITypeScriptServiceClient,
+        lspClient: LspClient,
         onCaseInsensitiveFileSystem: boolean,
     ) {
         this.client = client;
+        this.lspClient = lspClient;
         this.modeIds = new Set<string>(languageModeIds.jsTsLanguageModes);
 
         const pathNormalizer = (path: URI) => this.client.toTsFilePath(path.toString());
@@ -251,7 +274,16 @@ export class LspDocuments {
 
     public openTextDocument(textDocument: lsp.TextDocumentItem): boolean {
         if (!this.modeIds.has(textDocument.languageId)) {
-            return false;
+            const detectedLanguageId = getModeFromFileUri(textDocument.uri);
+            if (detectedLanguageId) {
+                this.lspClient.logMessage({
+                    type: lsp.MessageType.Warning,
+                    message: `Invalid langaugeId "${textDocument.languageId}" provided for uri "${textDocument.uri}". Correcting to "${detectedLanguageId}"`,
+                });
+                textDocument.languageId = detectedLanguageId;
+            } else {
+                return false;
+            }
         }
         const resource = textDocument.uri;
         const filepath = this.client.toTsFilePath(resource);
diff --git a/src/lsp-server.spec.ts b/src/lsp-server.spec.ts
index d72948c1..f4627fd8 100644
--- a/src/lsp-server.spec.ts
+++ b/src/lsp-server.spec.ts
@@ -2423,3 +2423,24 @@ describe('linked editing', () => {
         ]);
     });
 });
+
+describe('handles invalid languageId', () => {
+    it('simple test', async () => {
+        const textDocument = {
+            uri: uri('foo.tsx'),
+            languageId: 'tsx',
+            version: 1,
+            text: 'let bar = <div></div>',
+        };
+        await openDocumentAndWaitForDiagnostics(server, textDocument);
+        const position = positionAfter(textDocument, '<div');
+        const linedEditRanges = await server.linkedEditingRange({
+            textDocument,
+            position,
+        });
+        expect(linedEditRanges?.ranges).toStrictEqual([
+            { start: { line: 0, character: 11 }, end: { line: 0, character: 14 } },
+            { start: { line: 0, character: 17 }, end: { line: 0, character: 20 } },
+        ]);
+    });
+});
diff --git a/src/lsp-server.ts b/src/lsp-server.ts
index 99902fc3..5b8cd394 100644
--- a/src/lsp-server.ts
+++ b/src/lsp-server.ts
@@ -350,7 +350,7 @@ export class LspServer {
         }
 
         if (!this.tsClient.openTextDocument(params.textDocument)) {
-            throw new Error(`Cannot open document '${params.textDocument.uri}'.`);
+            throw new Error(`Cannot open document '${params.textDocument.uri}' (languageId: ${params.textDocument.languageId}).`);
         }
     }
 
diff --git a/src/ts-client.ts b/src/ts-client.ts
index 5259fa5d..27d10a8d 100644
--- a/src/ts-client.ts
+++ b/src/ts-client.ts
@@ -171,7 +171,7 @@ export class TsClient implements ITypeScriptServiceClient {
         logger: Logger,
         lspClient: LspClient,
     ) {
-        this.documents = new LspDocuments(this, onCaseInsensitiveFileSystem);
+        this.documents = new LspDocuments(this, lspClient, onCaseInsensitiveFileSystem);
         this.logger = new PrefixingLogger(logger, '[tsclient]');
         this.tsserverLogger = new PrefixingLogger(this.logger, '[tsserver]');
         this.lspClient = lspClient;